CVE-2026-42766

Issue summary: A specially crafted password-encrypted CMS message can trigger a NULL pointer dereference during CMS decryption.

Impact summary: This NULL pointer dereference leads to an application crash and a Denial of Service.

The CMS PasswordRecipientInfo.keyDerivationAlgorithm field is defined as OPTIONAL in the ASN.1 specification and may therefore be absent in specially crafted inputs. During the password-based CMS decryption the OpenSSL CMS implementation dereferences this field without first checking whether it was present.

An attacker who supplies such a CMS message to an application performing password-based CMS decryption can trigger an application crash, leading to a Denial of Service.

Applications that process password-encrypted CMS messages may be affected.

The FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are not affected by this issue, as the affected code is outside the OpenSSL FIPS module boundary.

Issue summary: A specially crafted password-encrypted CMS message can trigger a NULL pointer dereference during CMS decryption. Impact summary: This NULL pointer dereference leads to an application crash and a Denial of Service. The CMS PasswordRecipientInfo.keyDerivationAlgorithm field is defined as OPTIONAL in the ASN.1 specification and may therefore be absent in specially crafted inputs. During the password-based CMS decryption the OpenSSL CMS implementation dereferences this field without first checking whether it was present. An attacker who supplies such a CMS message to an application performing password-based CMS decryption can trigger an application crash, leading to a Denial of Service. Applications that process password-encrypted CMS messages may be affected. The FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are not affected by this issue, as the affected code is outside the OpenSSL FIPS module boundary.

Issue summary: A specially crafted password-encrypted CMS message can trigger a NULL pointer dereference during CMS decryption.

Impact summary: This NULL pointer dereference leads to an application crash and a Denial of Service.

The CMS PasswordRecipientInfo.keyDerivationAlgorithm field is defined as OPTIONAL in the ASN.1 specification and may therefore be absent in specially crafted inputs. During the password-based CMS decryption the OpenSSL CMS implementation dereferences this field without first checking whether it was present.

An attacker who supplies such a CMS message to an application performing password-based CMS decryption can trigger an application crash, leading to a Denial of Service.

Applications that process password-encrypted CMS messages may be affected.

The FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are not affected by this issue, as the affected code is outside the OpenSSL FIPS module boundary.

OpenSSL is a robust, commercial-grade, and full-featured toolkit for the Transport Layer Security (TLS) and Secure Sockets Layer (SSL) protocols.

Security Fix(es):

Issue summary: Parsing a crafted DER-encoded ASN.1 structure with a primitive element whose content exceeds 2 gigabytes in length may cause a heap buffer over-read on 64-bit Unix and Unix-like platforms.

Impact summary: The heap buffer over-read may crash the application (Denial of Service) or to load into the decoded ASN.1 object contents of memory beyond the end of the input buffer. More typically such ASN.1 elements would instead be truncated.

An integer truncation in OpenSSL's ASN.1 decoder causes the content length of an ASN.1 primitive element to be mishandled when it exceeds 2 gigabytes. In the worst case the truncated length is treated as a request to scan the binary content for a terminating zero byte, possibly causing OpenSSL to read either less than or beyond the end of the allocated buffer.

Applications that pass attacker-supplied data to d2i_X509(), d2i_PKCS7(), or any other d2i_* decoding function are affected. OpenSSL's own command-line tools are not vulnerable, as data read through the BIO layer is checked before it reaches the affected code. The issue only affects 64-bit Unix and Unix-like platforms; 32-bit platforms and 64-bit Windows are not affected.

The FIPS modules in 4.0, 3.6, 3.5, 3.4 and 3.0 are not affected by this issue, as the affected code is outside the OpenSSL FIPS module boundary.(CVE-2026-34180)

Issue summary: A specially crafted password-encrypted CMS message can trigger a NULL pointer dereference during CMS decryption.

Impact summary: This NULL pointer dereference leads to an application crash and a Denial of Service.

The CMS PasswordRecipientInfo.keyDerivationAlgorithm field is defined as OPTIONAL in the ASN.1 specification and may therefore be absent in specially crafted inputs. During the password-based CMS decryption the OpenSSL CMS implementation dereferences this field without first checking whether it was present.

An attacker who supplies such a CMS message to an application performing password-based CMS decryption can trigger an application crash, leading to a Denial of Service.

Applications that process password-encrypted CMS messages may be affected.

The FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are not affected by this issue, as the affected code is outside the OpenSSL FIPS module boundary.(CVE-2026-42766)

Issue summary: A specially crafted PKCS#7 or S/MIME signed message could trigger a use-after-free during PKCS#7 signature verification.

Impact summary: A use-after-free may result in process crashes, heap corruption, or potentially remote code execution.

When processing a PKCS#7 or S/MIME signed message, if the SignedData digestAlgorithms field is present as an empty ASN.1 SET, OpenSSL may incorrectly free a caller-owned BIO during PKCS7_verify(). A subsequent use of the BIO by the calling application results in a use-after-free condition.

In the common case this occurs when the application later calls BIO_free() on the BIO originally passed to PKCS7_verify(). Depending on allocator behavior and application-specific BIO usage patterns, this may result in a crash or other memory corruption. In some application contexts this may potentially be exploitable for remote code execution.

Applications that process PKCS#7 or S/MIME signed messages using OpenSSL PKCS#7 APIs may be affected. Applications using the CMS APIs for this processing are not affected.

The FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are not affected by this issue, as the affected code is outside the OpenSSL FIPS module boundary.(CVE-2026-45447)

Issue summary: A signed integer overflow when sizing the destination buffer for Unicode output in ASN1_mbstring_ncopy() can lead to a heap buffer overflow.

Impact summary: A heap buffer overflow may lead to a crash or possibly attacker controlled code execution or other undefined…

OpenSSL is a robust, commercial-grade, and full-featured toolkit for the Transport Layer Security (TLS) and Secure Sockets Layer (SSL) protocols.

Security Fix(es):

Issue summary: Parsing a crafted DER-encoded ASN.1 structure with a primitive element whose content exceeds 2 gigabytes in length may cause a heap buffer over-read on 64-bit Unix and Unix-like platforms.

Impact summary: The heap buffer over-read may crash the application (Denial of Service) or to load into the decoded ASN.1 object contents of memory beyond the end of the input buffer. More typically such ASN.1 elements would instead be truncated.

An integer truncation in OpenSSL's ASN.1 decoder causes the content length of an ASN.1 primitive element to be mishandled when it exceeds 2 gigabytes. In the worst case the truncated length is treated as a request to scan the binary content for a terminating zero byte, possibly causing OpenSSL to read either less than or beyond the end of the allocated buffer.

Applications that pass attacker-supplied data to d2i_X509(), d2i_PKCS7(), or any other d2i_* decoding function are affected. OpenSSL's own command-line tools are not vulnerable, as data read through the BIO layer is checked before it reaches the affected code. The issue only affects 64-bit Unix and Unix-like platforms; 32-bit platforms and 64-bit Windows are not affected.

The FIPS modules in 4.0, 3.6, 3.5, 3.4 and 3.0 are not affected by this issue, as the affected code is outside the OpenSSL FIPS module boundary.(CVE-2026-34180)

Issue summary: A specially crafted password-encrypted CMS message can trigger a NULL pointer dereference during CMS decryption.

Impact summary: This NULL pointer dereference leads to an application crash and a Denial of Service.

The CMS PasswordRecipientInfo.keyDerivationAlgorithm field is defined as OPTIONAL in the ASN.1 specification and may therefore be absent in specially crafted inputs. During the password-based CMS decryption the OpenSSL CMS implementation dereferences this field without first checking whether it was present.

An attacker who supplies such a CMS message to an application performing password-based CMS decryption can trigger an application crash, leading to a Denial of Service.

Applications that process password-encrypted CMS messages may be affected.

The FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are not affected by this issue, as the affected code is outside the OpenSSL FIPS module boundary.(CVE-2026-42766)

Issue summary: A specially crafted PKCS#7 or S/MIME signed message could trigger a use-after-free during PKCS#7 signature verification.

Impact summary: A use-after-free may result in process crashes, heap corruption, or potentially remote code execution.

When processing a PKCS#7 or S/MIME signed message, if the SignedData digestAlgorithms field is present as an empty ASN.1 SET, OpenSSL may incorrectly free a caller-owned BIO during PKCS7_verify(). A subsequent use of the BIO by the calling application results in a use-after-free condition.

In the common case this occurs when the application later calls BIO_free() on the BIO originally passed to PKCS7_verify(). Depending on allocator behavior and application-specific BIO usage patterns, this may result in a crash or other memory corruption. In some application contexts this may potentially be exploitable for remote code execution.

Applications that process PKCS#7 or S/MIME signed messages using OpenSSL PKCS#7 APIs may be affected. Applications using the CMS APIs for this processing are not affected.

The FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are not affected by this issue, as the affected code is outside the OpenSSL FIPS module boundary.(CVE-2026-45447)

Issue summary: A signed integer overflow when sizing the destination buffer for Unicode output in ASN1_mbstring_ncopy() can lead to a heap buffer overflow.

Impact summary: A heap buffer overflow may lead to a crash or possibly attacker controlled code execution or other undefined…

OpenSSL is a robust, commercial-grade, and full-featured toolkit for the Transport Layer Security (TLS) and Secure Sockets Layer (SSL) protocols.

Security Fix(es):

Issue summary: Parsing a crafted DER-encoded ASN.1 structure with a primitive element whose content exceeds 2 gigabytes in length may cause a heap buffer over-read on 64-bit Unix and Unix-like platforms.

Impact summary: The heap buffer over-read may crash the application (Denial of Service) or to load into the decoded ASN.1 object contents of memory beyond the end of the input buffer. More typically such ASN.1 elements would instead be truncated.

An integer truncation in OpenSSL's ASN.1 decoder causes the content length of an ASN.1 primitive element to be mishandled when it exceeds 2 gigabytes. In the worst case the truncated length is treated as a request to scan the binary content for a terminating zero byte, possibly causing OpenSSL to read either less than or beyond the end of the allocated buffer.

Applications that pass attacker-supplied data to d2i_X509(), d2i_PKCS7(), or any other d2i_* decoding function are affected. OpenSSL's own command-line tools are not vulnerable, as data read through the BIO layer is checked before it reaches the affected code. The issue only affects 64-bit Unix and Unix-like platforms; 32-bit platforms and 64-bit Windows are not affected.

The FIPS modules in 4.0, 3.6, 3.5, 3.4 and 3.0 are not affected by this issue, as the affected code is outside the OpenSSL FIPS module boundary.(CVE-2026-34180)

Issue Summary: Cryptographic Message Services (CMS) processing fails to perform sufficient input validation on the cipher and tag length fields of AuthEnvelopedData containers, leading to various potential compromises.

Impact Summary: Attackers making use of these vulnerabilities may achieve key-equivalent functionality for a given CMS recipient and/or bypass integrity validation for a given message.

In one use case, an attacker may send a CMS message containing AuthEnvelopedData with the cipher specified as a non-AEAD cipher. OpenSSL erroneously allows this selection, and attempts to decrypt and validate the message.

An on-path attacker who captures one legitimate AES-GCM AuthEnvelopedData addressed to the victim can re-emit it with the recipientInfos set left byte-for-byte intact, so the victim's private key still unwraps the genuine CEK (the content-encryption key), but with the inner OID rewritten to AES-256-OFB (Output Feedback Mode, an unauthenticated keystream mode) and with an attacker-chosen IV and ciphertext. The victim initializes AES-256-OFB under the real CEK, never consults the MAC field, and CMS_decrypt() returns success.

If the application under attack responds to the attacker with any indicator showing success or failure of the decryption effort, it is possible for the attacker to use this as an oracle to obtain key equivalent functionality for the CEK used for the chosen recipient of the message.

In another use case, an attacker can reduce the tag length of the chosen AEAD cipher for a given AuthEnvelopedData container to be a single byte long, allowing an attacker to brute force CMS decryption, producing an integrity bypass for applications that trust CMS_decrypt() to reject modified content.

The FIPS modules are not affected by this issue.(CVE-2026-34182)

Issue summary: A specially crafted password-encrypted CMS message can trigger a NULL pointer dereference during CMS decryption.

Impact summary: This NULL pointer dereference leads to an application crash and a Denial of Service.

The CMS PasswordRecipientInfo.keyDerivationAlgorithm field is defined as OPTIONAL in the ASN.1 specification and may therefore be absent in specially crafted inputs. During the password-based CMS decryption the OpenSSL CMS implementation dereferences this field without first checking whether it was present.

An attacker who supplies such a CMS message to an application performing password-based CMS decryption…

OpenSSL is a robust, commercial-grade, and full-featured toolkit for the Transport Layer Security (TLS) and Secure Sockets Layer (SSL) protocols.

Security Fix(es):

Issue summary: Parsing a crafted DER-encoded ASN.1 structure with a primitive element whose content exceeds 2 gigabytes in length may cause a heap buffer over-read on 64-bit Unix and Unix-like platforms.

Impact summary: The heap buffer over-read may crash the application (Denial of Service) or to load into the decoded ASN.1 object contents of memory beyond the end of the input buffer. More typically such ASN.1 elements would instead be truncated.

An integer truncation in OpenSSL's ASN.1 decoder causes the content length of an ASN.1 primitive element to be mishandled when it exceeds 2 gigabytes. In the worst case the truncated length is treated as a request to scan the binary content for a terminating zero byte, possibly causing OpenSSL to read either less than or beyond the end of the allocated buffer.

Applications that pass attacker-supplied data to d2i_X509(), d2i_PKCS7(), or any other d2i_* decoding function are affected. OpenSSL's own command-line tools are not vulnerable, as data read through the BIO layer is checked before it reaches the affected code. The issue only affects 64-bit Unix and Unix-like platforms; 32-bit platforms and 64-bit Windows are not affected.

The FIPS modules in 4.0, 3.6, 3.5, 3.4 and 3.0 are not affected by this issue, as the affected code is outside the OpenSSL FIPS module boundary.(CVE-2026-34180)

Issue Summary: Cryptographic Message Services (CMS) processing fails to perform sufficient input validation on the cipher and tag length fields of AuthEnvelopedData containers, leading to various potential compromises.

Impact Summary: Attackers making use of these vulnerabilities may achieve key-equivalent functionality for a given CMS recipient and/or bypass integrity validation for a given message.

In one use case, an attacker may send a CMS message containing AuthEnvelopedData with the cipher specified as a non-AEAD cipher. OpenSSL erroneously allows this selection, and attempts to decrypt and validate the message.

An on-path attacker who captures one legitimate AES-GCM AuthEnvelopedData addressed to the victim can re-emit it with the recipientInfos set left byte-for-byte intact, so the victim's private key still unwraps the genuine CEK (the content-encryption key), but with the inner OID rewritten to AES-256-OFB (Output Feedback Mode, an unauthenticated keystream mode) and with an attacker-chosen IV and ciphertext. The victim initializes AES-256-OFB under the real CEK, never consults the MAC field, and CMS_decrypt() returns success.

If the application under attack responds to the attacker with any indicator showing success or failure of the decryption effort, it is possible for the attacker to use this as an oracle to obtain key equivalent functionality for the CEK used for the chosen recipient of the message.

In another use case, an attacker can reduce the tag length of the chosen AEAD cipher for a given AuthEnvelopedData container to be a single byte long, allowing an attacker to brute force CMS decryption, producing an integrity bypass for applications that trust CMS_decrypt() to reject modified content.

The FIPS modules are not affected by this issue.(CVE-2026-34182)

Issue summary: A specially crafted password-encrypted CMS message can trigger a NULL pointer dereference during CMS decryption.

Impact summary: This NULL pointer dereference leads to an application crash and a Denial of Service.

The CMS PasswordRecipientInfo.keyDerivationAlgorithm field is defined as OPTIONAL in the ASN.1 specification and may therefore be absent in specially crafted inputs. During the password-based CMS decryption the OpenSSL CMS implementation dereferences this field without first checking whether it was present.

An attacker who supplies such a CMS message to an application performing password-based CMS decryption…

OpenSSL is a robust, commercial-grade, and full-featured toolkit for the Transport Layer Security (TLS) and Secure Sockets Layer (SSL) protocols.

Security Fix(es):

Issue summary: Parsing a crafted DER-encoded ASN.1 structure with a primitive element whose content exceeds 2 gigabytes in length may cause a heap buffer over-read on 64-bit Unix and Unix-like platforms.

Impact summary: The heap buffer over-read may crash the application (Denial of Service) or to load into the decoded ASN.1 object contents of memory beyond the end of the input buffer. More typically such ASN.1 elements would instead be truncated.

An integer truncation in OpenSSL's ASN.1 decoder causes the content length of an ASN.1 primitive element to be mishandled when it exceeds 2 gigabytes. In the worst case the truncated length is treated as a request to scan the binary content for a terminating zero byte, possibly causing OpenSSL to read either less than or beyond the end of the allocated buffer.

Applications that pass attacker-supplied data to d2i_X509(), d2i_PKCS7(), or any other d2i_* decoding function are affected. OpenSSL's own command-line tools are not vulnerable, as data read through the BIO layer is checked before it reaches the affected code. The issue only affects 64-bit Unix and Unix-like platforms; 32-bit platforms and 64-bit Windows are not affected.

The FIPS modules in 4.0, 3.6, 3.5, 3.4 and 3.0 are not affected by this issue, as the affected code is outside the OpenSSL FIPS module boundary.(CVE-2026-34180)

Issue summary: A specially crafted password-encrypted CMS message can trigger a NULL pointer dereference during CMS decryption.

Impact summary: This NULL pointer dereference leads to an application crash and a Denial of Service.

The CMS PasswordRecipientInfo.keyDerivationAlgorithm field is defined as OPTIONAL in the ASN.1 specification and may therefore be absent in specially crafted inputs. During the password-based CMS decryption the OpenSSL CMS implementation dereferences this field without first checking whether it was present.

An attacker who supplies such a CMS message to an application performing password-based CMS decryption can trigger an application crash, leading to a Denial of Service.

Applications that process password-encrypted CMS messages may be affected.

The FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are not affected by this issue, as the affected code is outside the OpenSSL FIPS module boundary.(CVE-2026-42766)

Issue summary: A specially crafted PKCS#7 or S/MIME signed message could trigger a use-after-free during PKCS#7 signature verification.

Impact summary: A use-after-free may result in process crashes, heap corruption, or potentially remote code execution.

When processing a PKCS#7 or S/MIME signed message, if the SignedData digestAlgorithms field is present as an empty ASN.1 SET, OpenSSL may incorrectly free a caller-owned BIO during PKCS7_verify(). A subsequent use of the BIO by the calling application results in a use-after-free condition.

In the common case this occurs when the application later calls BIO_free() on the BIO originally passed to PKCS7_verify(). Depending on allocator behavior and application-specific BIO usage patterns, this may result in a crash or other memory corruption. In some application contexts this may potentially be exploitable for remote code execution.

Applications that process PKCS#7 or S/MIME signed messages using OpenSSL PKCS#7 APIs may be affected. Applications using the CMS APIs for this processing are not affected.

The FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are not affected by this issue, as the affected code is outside the OpenSSL FIPS module boundary.(CVE-2026-45447)

Issue summary: A signed integer overflow when sizing the destination buffer for Unicode output in ASN1_mbstring_ncopy() can lead to a heap buffer overflow.

Impact summary: A heap buffer overflow may lead to a crash or possibly attacker controlled code execution or other undefined…

OpenSSL is a robust, commercial-grade, and full-featured toolkit for the Transport Layer Security (TLS) and Secure Sockets Layer (SSL) protocols.

Security Fix(es):

Issue summary: Parsing a crafted DER-encoded ASN.1 structure with a primitive element whose content exceeds 2 gigabytes in length may cause a heap buffer over-read on 64-bit Unix and Unix-like platforms.

Impact summary: The heap buffer over-read may crash the application (Denial of Service) or to load into the decoded ASN.1 object contents of memory beyond the end of the input buffer. More typically such ASN.1 elements would instead be truncated.

An integer truncation in OpenSSL's ASN.1 decoder causes the content length of an ASN.1 primitive element to be mishandled when it exceeds 2 gigabytes. In the worst case the truncated length is treated as a request to scan the binary content for a terminating zero byte, possibly causing OpenSSL to read either less than or beyond the end of the allocated buffer.

Applications that pass attacker-supplied data to d2i_X509(), d2i_PKCS7(), or any other d2i_* decoding function are affected. OpenSSL's own command-line tools are not vulnerable, as data read through the BIO layer is checked before it reaches the affected code. The issue only affects 64-bit Unix and Unix-like platforms; 32-bit platforms and 64-bit Windows are not affected.

The FIPS modules in 4.0, 3.6, 3.5, 3.4 and 3.0 are not affected by this issue, as the affected code is outside the OpenSSL FIPS module boundary.(CVE-2026-34180)

Issue summary: A specially crafted password-encrypted CMS message can trigger a NULL pointer dereference during CMS decryption.

Impact summary: This NULL pointer dereference leads to an application crash and a Denial of Service.

The CMS PasswordRecipientInfo.keyDerivationAlgorithm field is defined as OPTIONAL in the ASN.1 specification and may therefore be absent in specially crafted inputs. During the password-based CMS decryption the OpenSSL CMS implementation dereferences this field without first checking whether it was present.

An attacker who supplies such a CMS message to an application performing password-based CMS decryption can trigger an application crash, leading to a Denial of Service.

Applications that process password-encrypted CMS messages may be affected.

The FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are not affected by this issue, as the affected code is outside the OpenSSL FIPS module boundary.(CVE-2026-42766)

Issue summary: A specially crafted PKCS#7 or S/MIME signed message could trigger a use-after-free during PKCS#7 signature verification.

Impact summary: A use-after-free may result in process crashes, heap corruption, or potentially remote code execution.

When processing a PKCS#7 or S/MIME signed message, if the SignedData digestAlgorithms field is present as an empty ASN.1 SET, OpenSSL may incorrectly free a caller-owned BIO during PKCS7_verify(). A subsequent use of the BIO by the calling application results in a use-after-free condition.

In the common case this occurs when the application later calls BIO_free() on the BIO originally passed to PKCS7_verify(). Depending on allocator behavior and application-specific BIO usage patterns, this may result in a crash or other memory corruption. In some application contexts this may potentially be exploitable for remote code execution.

Applications that process PKCS#7 or S/MIME signed messages using OpenSSL PKCS#7 APIs may be affected. Applications using the CMS APIs for this processing are not affected.

The FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are not affected by this issue, as the affected code is outside the OpenSSL FIPS module boundary.(CVE-2026-45447)

Issue summary: A signed integer overflow when sizing the destination buffer for Unicode output in ASN1_mbstring_ncopy() can lead to a heap buffer overflow.

Impact summary: A heap buffer overflow may lead to a crash or possibly attacker controlled code execution or other undefined…

EDK II is a modern, feature-rich, cross-platform firmware development environment for the UEFI and PI specifications.

Security Fix(es):

Issue summary: A specially crafted password-encrypted CMS message can trigger a NULL pointer dereference during CMS decryption.

Impact summary: This NULL pointer dereference leads to an application crash and a Denial of Service.

The CMS PasswordRecipientInfo.keyDerivationAlgorithm field is defined as OPTIONAL in the ASN.1 specification and may therefore be absent in specially crafted inputs. During the password-based CMS decryption the OpenSSL CMS implementation dereferences this field without first checking whether it was present.

An attacker who supplies such a CMS message to an application performing password-based CMS decryption can trigger an application crash, leading to a Denial of Service.

Applications that process password-encrypted CMS messages may be affected.

The FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are not affected by this issue, as the affected code is outside the OpenSSL FIPS module boundary.(CVE-2026-42766)

Issue summary: An attacker-controlled CMP (Certificate Management Protocol) server could trigger a NULL pointer dereference in a CMP client application.

Impact summary: A NULL pointer dereference causes a crash of the application and a Denial of Service.

An attacker controlling a CMP server (or acting as a man-in-the-middle) could craft a CMP response containing a CRMF (Certificate Request Message Format) CertRepMessage with an EncryptedValue structure where the symmAlg field has an algorithm OID but no parameters field. When the OpenSSL CMP client processes this response, the NULL dereference occurs, causing a crash of the CMP client.

Applications that process untrusted CMP/CRMF messages may be affected.

The FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are not affected by this issue, as the affected code is outside the OpenSSL FIPS module boundary.(CVE-2026-42767)

Issue summary: The CMS_decrypt and PKCS7_decrypt functions are vulnerable to Bleichenbacher-style attack when an attacker is able to provide the CMS or S/MIME messages and observe the error code and/or decryption output.

Impact summary: The Bleichenbacher-style attack allows an attacker to use the victim's vulnerable application as a way to decrypt or sign messages with the victim's private RSA key.

The attack is possible in 2 variants.

1. The decryption API (CMS_decrypt(), PKCS7_decrypt()) is used without providing the recipient certificate. In this case OpenSSL iterates over every KeyTransRecipientInfo (KTRI) without stopping at the first success.

An attacker who authors a message with two KTRI entries — the first one wrapping a real CEK under the victim's public key, the second with an arbitrary probe ciphertext — obtains opportunity to iterate the 2nd KTRI to get a valid PKCS#1 v1.5 padding if the error code of the application is available.

That is a Bleichenbacher oracle (Bleichenbacher, CRYPTO '98): an adaptive-chosen-ciphertext side channel from which the attacker decrypts any RSA ciphertext to the victim's key or forges any PKCS#1 v1.5 signature under it.

2. When the decryption API (CMS_decrypt(), PKCS7_decrypt()) is provided with the recipient certificate, and the recipient is not found, a random key is substituted.

An attacker who authors a message and is able to compare both error code and the result of the decryption, can mount a Bleichenbacher oracle.

We are not aware of any applications that provide a remote attacker an opportunity to mount an attack described in these scenarios. We consider the existence of such application very unlikely, and for this reason this CVE has been evaluated as Low severity.

To avoid these attacks, when RSA PKCS#1 v1.5 Key Transport is in use, the invoked EVP_PKEY_decrypt() will use the implicit rejection mechanism described in draft-irtf-cfrg-rsa-guidance. In previous OpenSSL releases the implicit rejection was…

EDK II is a modern, feature-rich, cross-platform firmware development environment for the UEFI and PI specifications.

Security Fix(es):

Issue summary: A specially crafted password-encrypted CMS message can trigger a NULL pointer dereference during CMS decryption.

Impact summary: This NULL pointer dereference leads to an application crash and a Denial of Service.

The CMS PasswordRecipientInfo.keyDerivationAlgorithm field is defined as OPTIONAL in the ASN.1 specification and may therefore be absent in specially crafted inputs. During the password-based CMS decryption the OpenSSL CMS implementation dereferences this field without first checking whether it was present.

An attacker who supplies such a CMS message to an application performing password-based CMS decryption can trigger an application crash, leading to a Denial of Service.

Applications that process password-encrypted CMS messages may be affected.

The FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are not affected by this issue, as the affected code is outside the OpenSSL FIPS module boundary.(CVE-2026-42766)

Issue summary: An attacker-controlled CMP (Certificate Management Protocol) server could trigger a NULL pointer dereference in a CMP client application.

Impact summary: A NULL pointer dereference causes a crash of the application and a Denial of Service.

An attacker controlling a CMP server (or acting as a man-in-the-middle) could craft a CMP response containing a CRMF (Certificate Request Message Format) CertRepMessage with an EncryptedValue structure where the symmAlg field has an algorithm OID but no parameters field. When the OpenSSL CMP client processes this response, the NULL dereference occurs, causing a crash of the CMP client.

Applications that process untrusted CMP/CRMF messages may be affected.

The FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are not affected by this issue, as the affected code is outside the OpenSSL FIPS module boundary.(CVE-2026-42767)

Issue summary: The CMS_decrypt and PKCS7_decrypt functions are vulnerable to Bleichenbacher-style attack when an attacker is able to provide the CMS or S/MIME messages and observe the error code and/or decryption output.

Impact summary: The Bleichenbacher-style attack allows an attacker to use the victim's vulnerable application as a way to decrypt or sign messages with the victim's private RSA key.

The attack is possible in 2 variants.

1. The decryption API (CMS_decrypt(), PKCS7_decrypt()) is used without providing the recipient certificate. In this case OpenSSL iterates over every KeyTransRecipientInfo (KTRI) without stopping at the first success.

An attacker who authors a message with two KTRI entries — the first one wrapping a real CEK under the victim's public key, the second with an arbitrary probe ciphertext — obtains opportunity to iterate the 2nd KTRI to get a valid PKCS#1 v1.5 padding if the error code of the application is available.

That is a Bleichenbacher oracle (Bleichenbacher, CRYPTO '98): an adaptive-chosen-ciphertext side channel from which the attacker decrypts any RSA ciphertext to the victim's key or forges any PKCS#1 v1.5 signature under it.

2. When the decryption API (CMS_decrypt(), PKCS7_decrypt()) is provided with the recipient certificate, and the recipient is not found, a random key is substituted.

An attacker who authors a message and is able to compare both error code and the result of the decryption, can mount a Bleichenbacher oracle.

We are not aware of any applications that provide a remote attacker an opportunity to mount an attack described in these scenarios. We consider the existence of such application very unlikely, and for this reason this CVE has been evaluated as Low severity.

To avoid these attacks, when RSA PKCS#1 v1.5 Key Transport is in use, the invoked EVP_PKEY_decrypt() will use the implicit rejection mechanism described in draft-irtf-cfrg-rsa-guidance. In previous OpenSSL releases the implicit rejection was…

EDK II is a modern, feature-rich, cross-platform firmware development environment for the UEFI and PI specifications.

Security Fix(es):

Issue summary: A specially crafted password-encrypted CMS message can trigger a NULL pointer dereference during CMS decryption.

Impact summary: This NULL pointer dereference leads to an application crash and a Denial of Service.

The CMS PasswordRecipientInfo.keyDerivationAlgorithm field is defined as OPTIONAL in the ASN.1 specification and may therefore be absent in specially crafted inputs. During the password-based CMS decryption the OpenSSL CMS implementation dereferences this field without first checking whether it was present.

An attacker who supplies such a CMS message to an application performing password-based CMS decryption can trigger an application crash, leading to a Denial of Service.

Applications that process password-encrypted CMS messages may be affected.

The FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are not affected by this issue, as the affected code is outside the OpenSSL FIPS module boundary.(CVE-2026-42766)

Issue summary: The CMS_decrypt and PKCS7_decrypt functions are vulnerable to Bleichenbacher-style attack when an attacker is able to provide the CMS or S/MIME messages and observe the error code and/or decryption output.

Impact summary: The Bleichenbacher-style attack allows an attacker to use the victim's vulnerable application as a way to decrypt or sign messages with the victim's private RSA key.

The attack is possible in 2 variants.

1. The decryption API (CMS_decrypt(), PKCS7_decrypt()) is used without providing the recipient certificate. In this case OpenSSL iterates over every KeyTransRecipientInfo (KTRI) without stopping at the first success.

An attacker who authors a message with two KTRI entries — the first one wrapping a real CEK under the victim's public key, the second with an arbitrary probe ciphertext — obtains opportunity to iterate the 2nd KTRI to get a valid PKCS#1 v1.5 padding if the error code of the application is available.

That is a Bleichenbacher oracle (Bleichenbacher, CRYPTO '98): an adaptive-chosen-ciphertext side channel from which the attacker decrypts any RSA ciphertext to the victim's key or forges any PKCS#1 v1.5 signature under it.

2. When the decryption API (CMS_decrypt(), PKCS7_decrypt()) is provided with the recipient certificate, and the recipient is not found, a random key is substituted.

An attacker who authors a message and is able to compare both error code and the result of the decryption, can mount a Bleichenbacher oracle.

We are not aware of any applications that provide a remote attacker an opportunity to mount an attack described in these scenarios. We consider the existence of such application very unlikely, and for this reason this CVE has been evaluated as Low severity.

To avoid these attacks, when RSA PKCS#1 v1.5 Key Transport is in use, the invoked EVP_PKEY_decrypt() will use the implicit rejection mechanism described in draft-irtf-cfrg-rsa-guidance. In previous OpenSSL releases the implicit rejection was explicitly disabled.

The implicit rejection mechanism always returns a plaintext value, the symmetric key. This result is deterministic for the ciphertext and the private key. The length of the decryption result can happen to match the length of the key of the symmetric cipher that was used for the content encryption. When a certificate is not provided, the last RecipientInfo producing a key that looks valid will be used. It may cause getting garbage content on decryption. As a proper way to deal with this a recipient certificate has to be provided to identify the particular RecipientInfo for decryption.

The FIPS modules in 4.0, 3.6, 3.5, and 3.4 are not affected by this issue, as CMS and S/MIME processing happens outside the OpenSSL FIPS module boundary.(CVE-2026-42768)

EDK II is a modern, feature-rich, cross-platform firmware development environment for the UEFI and PI specifications.

Security Fix(es):

Issue summary: A specially crafted password-encrypted CMS message can trigger a NULL pointer dereference during CMS decryption.

Impact summary: This NULL pointer dereference leads to an application crash and a Denial of Service.

The CMS PasswordRecipientInfo.keyDerivationAlgorithm field is defined as OPTIONAL in the ASN.1 specification and may therefore be absent in specially crafted inputs. During the password-based CMS decryption the OpenSSL CMS implementation dereferences this field without first checking whether it was present.

An attacker who supplies such a CMS message to an application performing password-based CMS decryption can trigger an application crash, leading to a Denial of Service.

Applications that process password-encrypted CMS messages may be affected.

The FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are not affected by this issue, as the affected code is outside the OpenSSL FIPS module boundary.(CVE-2026-42766)

Issue summary: The CMS_decrypt and PKCS7_decrypt functions are vulnerable to Bleichenbacher-style attack when an attacker is able to provide the CMS or S/MIME messages and observe the error code and/or decryption output.

Impact summary: The Bleichenbacher-style attack allows an attacker to use the victim's vulnerable application as a way to decrypt or sign messages with the victim's private RSA key.

The attack is possible in 2 variants.

1. The decryption API (CMS_decrypt(), PKCS7_decrypt()) is used without providing the recipient certificate. In this case OpenSSL iterates over every KeyTransRecipientInfo (KTRI) without stopping at the first success.

An attacker who authors a message with two KTRI entries — the first one wrapping a real CEK under the victim's public key, the second with an arbitrary probe ciphertext — obtains opportunity to iterate the 2nd KTRI to get a valid PKCS#1 v1.5 padding if the error code of the application is available.

That is a Bleichenbacher oracle (Bleichenbacher, CRYPTO '98): an adaptive-chosen-ciphertext side channel from which the attacker decrypts any RSA ciphertext to the victim's key or forges any PKCS#1 v1.5 signature under it.

2. When the decryption API (CMS_decrypt(), PKCS7_decrypt()) is provided with the recipient certificate, and the recipient is not found, a random key is substituted.

An attacker who authors a message and is able to compare both error code and the result of the decryption, can mount a Bleichenbacher oracle.

We are not aware of any applications that provide a remote attacker an opportunity to mount an attack described in these scenarios. We consider the existence of such application very unlikely, and for this reason this CVE has been evaluated as Low severity.

To avoid these attacks, when RSA PKCS#1 v1.5 Key Transport is in use, the invoked EVP_PKEY_decrypt() will use the implicit rejection mechanism described in draft-irtf-cfrg-rsa-guidance. In previous OpenSSL releases the implicit rejection was explicitly disabled.

The implicit rejection mechanism always returns a plaintext value, the symmetric key. This result is deterministic for the ciphertext and the private key. The length of the decryption result can happen to match the length of the key of the symmetric cipher that was used for the content encryption. When a certificate is not provided, the last RecipientInfo producing a key that looks valid will be used. It may cause getting garbage content on decryption. As a proper way to deal with this a recipient certificate has to be provided to identify the particular RecipientInfo for decryption.

The FIPS modules in 4.0, 3.6, 3.5, and 3.4 are not affected by this issue, as CMS and S/MIME processing happens outside the OpenSSL FIPS module boundary.(CVE-2026-42768)

EDK II is a modern, feature-rich, cross-platform firmware development environment for the UEFI and PI specifications.

Security Fix(es):

Issue summary: A specially crafted password-encrypted CMS message can trigger a NULL pointer dereference during CMS decryption.

Impact summary: This NULL pointer dereference leads to an application crash and a Denial of Service.

The CMS PasswordRecipientInfo.keyDerivationAlgorithm field is defined as OPTIONAL in the ASN.1 specification and may therefore be absent in specially crafted inputs. During the password-based CMS decryption the OpenSSL CMS implementation dereferences this field without first checking whether it was present.

An attacker who supplies such a CMS message to an application performing password-based CMS decryption can trigger an application crash, leading to a Denial of Service.

Applications that process password-encrypted CMS messages may be affected.

The FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are not affected by this issue, as the affected code is outside the OpenSSL FIPS module boundary.(CVE-2026-42766)

Issue summary: An attacker-controlled CMP (Certificate Management Protocol) server could trigger a NULL pointer dereference in a CMP client application.

Impact summary: A NULL pointer dereference causes a crash of the application and a Denial of Service.

An attacker controlling a CMP server (or acting as a man-in-the-middle) could craft a CMP response containing a CRMF (Certificate Request Message Format) CertRepMessage with an EncryptedValue structure where the symmAlg field has an algorithm OID but no parameters field. When the OpenSSL CMP client processes this response, the NULL dereference occurs, causing a crash of the CMP client.

Applications that process untrusted CMP/CRMF messages may be affected.

The FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are not affected by this issue, as the affected code is outside the OpenSSL FIPS module boundary.(CVE-2026-42767)

Issue summary: The CMS_decrypt and PKCS7_decrypt functions are vulnerable to Bleichenbacher-style attack when an attacker is able to provide the CMS or S/MIME messages and observe the error code and/or decryption output.

Impact summary: The Bleichenbacher-style attack allows an attacker to use the victim's vulnerable application as a way to decrypt or sign messages with the victim's private RSA key.

The attack is possible in 2 variants.

1. The decryption API (CMS_decrypt(), PKCS7_decrypt()) is used without providing the recipient certificate. In this case OpenSSL iterates over every KeyTransRecipientInfo (KTRI) without stopping at the first success.

An attacker who authors a message with two KTRI entries — the first one wrapping a real CEK under the victim's public key, the second with an arbitrary probe ciphertext — obtains opportunity to iterate the 2nd KTRI to get a valid PKCS#1 v1.5 padding if the error code of the application is available.

That is a Bleichenbacher oracle (Bleichenbacher, CRYPTO '98): an adaptive-chosen-ciphertext side channel from which the attacker decrypts any RSA ciphertext to the victim's key or forges any PKCS#1 v1.5 signature under it.

2. When the decryption API (CMS_decrypt(), PKCS7_decrypt()) is provided with the recipient certificate, and the recipient is not found, a random key is substituted.

An attacker who authors a message and is able to compare both error code and the result of the decryption, can mount a Bleichenbacher oracle.

We are not aware of any applications that provide a remote attacker an opportunity to mount an attack described in these scenarios. We consider the existence of such application very unlikely, and for this reason this CVE has been evaluated as Low severity.

To avoid these attacks, when RSA PKCS#1 v1.5 Key Transport is in use, the invoked EVP_PKEY_decrypt() will use the implicit rejection mechanism described in draft-irtf-cfrg-rsa-guidance. In previous OpenSSL releases the implicit rejection was…

OpenSSL is a toolkit that implements the Secure Sockets Layer (SSL) and Transport Layer Security (TLS) protocols, as well as a full-strength general-purpose cryptography library.

Security Fix(es):

• openssl: OpenSSL: Heap buffer overflow due to signed integer overflow in Unicode output sizing (CVE-2026-7383)

• openssl: OpenSSL: Denial of Service due to heap out-of-bounds read in CMS password-based decryption (CVE-2026-9076)

• openssl: OpenSSL: Heap buffer over-read in ASN.1 decoding can lead to denial of service or information disclosure. (CVE-2026-34180)

• openssl: PKCS#12 Files with PBMAC1 Are Accepted with Short HMAC Keys (CVE-2026-34181)

• openssl: CMS AuthEnvelopedData Processing May Accept Forged Messages (CVE-2026-34182)

• openssl: Unbounded Memory Growth in the QUIC PATH_CHALLENGE Handler (CVE-2026-34183)

• openssl: NULL pointer dereference in QUIC server initial packet handling (CVE-2026-42764)

• openssl: Possible NULL Dereference in Password-Based CMS Decryption (CVE-2026-42766)

• openssl: NULL Pointer Dereference in CRMF EncryptedValue Decryption (CVE-2026-42767)

• openssl: Multi-RecipientInfo Bleichenbacher Oracle in CMS_decrypt() and PKCS7_decrypt() (CVE-2026-42768)

• openssl: Trust-Anchor Substitution via cert/issuer Typo in CMP rootCaKeyUpdate (CVE-2026-42769)

• openssl: FFC-DH Peer Validation Uses Attacker-Supplied q (CVE-2026-42770)

• openssl: AES-OCB IV Ignored on EVP_Cipher() Path (CVE-2026-45445)

• openssl: Incorrect Tag Processing for Empty Messages in AES-GCM-SIV and AES-SIV modes (CVE-2026-45446)

• openssl: Heap Use-After-Free in OpenSSL PKCS7_verify() (CVE-2026-45447)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

OpenSSL is a toolkit that implements the Secure Sockets Layer (SSL) and Transport Layer Security (TLS) protocols, as well as a full-strength general-purpose cryptography library.

Security Fix(es):

• openssl: OpenSSL: Heap buffer overflow due to signed integer overflow in Unicode output sizing (CVE-2026-7383)

• openssl: OpenSSL: Denial of Service due to heap out-of-bounds read in CMS password-based decryption (CVE-2026-9076)

• openssl: OpenSSL: Heap buffer over-read in ASN.1 decoding can lead to denial of service or information disclosure. (CVE-2026-34180)

• openssl: PKCS#12 Files with PBMAC1 Are Accepted with Short HMAC Keys (CVE-2026-34181)

• openssl: CMS AuthEnvelopedData Processing May Accept Forged Messages (CVE-2026-34182)

• openssl: Unbounded Memory Growth in the QUIC PATH_CHALLENGE Handler (CVE-2026-34183)

• openssl: NULL pointer dereference in QUIC server initial packet handling (CVE-2026-42764)

• openssl: Possible NULL Dereference in Password-Based CMS Decryption (CVE-2026-42766)

• openssl: NULL Pointer Dereference in CRMF EncryptedValue Decryption (CVE-2026-42767)

• openssl: Multi-RecipientInfo Bleichenbacher Oracle in CMS_decrypt() and PKCS7_decrypt() (CVE-2026-42768)

• openssl: Trust-Anchor Substitution via cert/issuer Typo in CMP rootCaKeyUpdate (CVE-2026-42769)

• openssl: FFC-DH Peer Validation Uses Attacker-Supplied q (CVE-2026-42770)

• openssl: AES-OCB IV Ignored on EVP_Cipher() Path (CVE-2026-45445)

• openssl: Incorrect Tag Processing for Empty Messages in AES-GCM-SIV and AES-SIV modes (CVE-2026-45446)

• openssl: Heap Use-After-Free in OpenSSL PKCS7_verify() (CVE-2026-45447)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Issue summary: A specially crafted password-encrypted CMS message can trigger a NULL pointer dereference during CMS decryption. Impact summary: This NULL pointer dereference leads to an application crash and a Denial of Service. The CMS PasswordRecipientInfo.keyDerivationAlgorithm field is defined as OPTIONAL in the ASN.1 specification and may therefore be absent in specially crafted inputs. During the password-based CMS decryption the OpenSSL CMS implementation dereferences this field without first checking whether it was present. An attacker who supplies such a CMS message to an application performing password-based CMS decryption can trigger an application crash, leading to a Denial of Service. Applications that process password-encrypted CMS messages may be affected. The FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are not affected by this issue, as the affected code is outside the OpenSSL FIPS module boundary.

OpenSSL is a toolkit that implements the Secure Sockets Layer (SSL) and Transport Layer Security (TLS) protocols, as well as a full-strength general-purpose cryptography library.

Security Fix(es):

• openssl: OpenSSL: Heap buffer overflow due to signed integer overflow in Unicode output sizing (CVE-2026-7383)
• openssl: OpenSSL: Denial of Service due to heap out-of-bounds read in CMS password-based decryption (CVE-2026-9076)
• openssl: OpenSSL: Heap buffer over-read in ASN.1 decoding can lead to denial of service or information disclosure. (CVE-2026-34180)
• openssl: PKCS#12 Files with PBMAC1 Are Accepted with Short HMAC Keys (CVE-2026-34181)
• openssl: CMS AuthEnvelopedData Processing May Accept Forged Messages (CVE-2026-34182)
• openssl: Unbounded Memory Growth in the QUIC PATH_CHALLENGE Handler (CVE-2026-34183)
• openssl: NULL pointer dereference in QUIC server initial packet handling (CVE-2026-42764)
• openssl: Possible NULL Dereference in Password-Based CMS Decryption (CVE-2026-42766)
• openssl: NULL Pointer Dereference in CRMF EncryptedValue Decryption (CVE-2026-42767)
• openssl: Multi-RecipientInfo Bleichenbacher Oracle in CMS_decrypt() and PKCS7_decrypt() (CVE-2026-42768)
• openssl: Trust-Anchor Substitution via cert/issuer Typo in CMP rootCaKeyUpdate (CVE-2026-42769)
• openssl: FFC-DH Peer Validation Uses Attacker-Supplied q (CVE-2026-42770)
• openssl: AES-OCB IV Ignored on EVP_Cipher() Path (CVE-2026-45445)
• openssl: Incorrect Tag Processing for Empty Messages in AES-GCM-SIV and AES-SIV modes (CVE-2026-45446)
• openssl: Heap Use-After-Free in OpenSSL PKCS7_verify() (CVE-2026-45447)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

OpenSSL is a toolkit that implements the Secure Sockets Layer (SSL) and Transport Layer Security (TLS) protocols, as well as a full-strength general-purpose cryptography library.

Security Fix(es):

• openssl: OpenSSL: Heap buffer overflow due to signed integer overflow in Unicode output sizing (CVE-2026-7383)
• openssl: OpenSSL: Denial of Service due to heap out-of-bounds read in CMS password-based decryption (CVE-2026-9076)
• openssl: OpenSSL: Heap buffer over-read in ASN.1 decoding can lead to denial of service or information disclosure. (CVE-2026-34180)
• openssl: PKCS#12 Files with PBMAC1 Are Accepted with Short HMAC Keys (CVE-2026-34181)
• openssl: CMS AuthEnvelopedData Processing May Accept Forged Messages (CVE-2026-34182)
• openssl: Unbounded Memory Growth in the QUIC PATH_CHALLENGE Handler (CVE-2026-34183)
• openssl: NULL pointer dereference in QUIC server initial packet handling (CVE-2026-42764)
• openssl: Possible NULL Dereference in Password-Based CMS Decryption (CVE-2026-42766)
• openssl: NULL Pointer Dereference in CRMF EncryptedValue Decryption (CVE-2026-42767)
• openssl: Multi-RecipientInfo Bleichenbacher Oracle in CMS_decrypt() and PKCS7_decrypt() (CVE-2026-42768)
• openssl: Trust-Anchor Substitution via cert/issuer Typo in CMP rootCaKeyUpdate (CVE-2026-42769)
• openssl: FFC-DH Peer Validation Uses Attacker-Supplied q (CVE-2026-42770)
• openssl: AES-OCB IV Ignored on EVP_Cipher() Path (CVE-2026-45445)
• openssl: Incorrect Tag Processing for Empty Messages in AES-GCM-SIV and AES-SIV modes (CVE-2026-45446)
• openssl: Heap Use-After-Free in OpenSSL PKCS7_verify() (CVE-2026-45447)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Issue summary: A specially crafted password-encrypted CMS message can trigger a NULL pointer dereference during CMS decryption.

Impact summary: This NULL pointer dereference leads to an application crash and a Denial of Service.

The CMS PasswordRecipientInfo.keyDerivationAlgorithm field is defined as OPTIONAL in the ASN.1 specification and may therefore be absent in specially crafted inputs. During the password-based CMS decryption the OpenSSL CMS implementation dereferences this field without first checking whether it was present.

An attacker who supplies such a CMS message to an application performing password-based CMS decryption can trigger an application crash, leading to a Denial of Service.

Applications that process password-encrypted CMS messages may be affected.

The FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are not affected by this issue, as the affected code is outside the OpenSSL FIPS module boundary.

Issue summary: A specially crafted password-encrypted CMS message can trigger a NULL pointer dereference during CMS decryption.

Impact summary: This NULL pointer dereference leads to an application crash and a Denial of Service.

The CMS PasswordRecipientInfo.keyDerivationAlgorithm field is defined as OPTIONAL in the ASN.1 specification and may therefore be absent in specially crafted inputs. During the password-based CMS decryption the OpenSSL CMS implementation dereferences this field without first checking whether it was present.

An attacker who supplies such a CMS message to an application performing password-based CMS decryption can trigger an application crash, leading to a Denial of Service.

Applications that process password-encrypted CMS messages may be affected.

The FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are not affected by this issue, as the affected code is outside the OpenSSL FIPS module boundary.

Issue summary: A specially crafted password-encrypted CMS message can trigger a NULL pointer dereference during CMS decryption.

Impact summary: This NULL pointer dereference leads to an application crash and a Denial of Service.

The CMS PasswordRecipientInfo.keyDerivationAlgorithm field is defined as OPTIONAL in the ASN.1 specification and may therefore be absent in specially crafted inputs. During the password-based CMS decryption the OpenSSL CMS implementation dereferences this field without first checking whether it was present.

An attacker who supplies such a CMS message to an application performing password-based CMS decryption can trigger an application crash, leading to a Denial of Service.

Applications that process password-encrypted CMS messages may be affected.

The FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are not affected by this issue, as the affected code is outside the OpenSSL FIPS module boundary.

• SECURITY UPDATE: Heap buffer overflow in ASN1_mbstring_ncopy() where the destination length for BMPSTRING and UNIVERSALSTRING output is computed by a signed left shift that can overflow int, producing an undersized allocation followed by out-of-bounds writes for oversized attacker-controlled inputs reaching ASN1_mbstring_copy() or ASN1_mbstring_ncopy() directly.
  • debian/patches/CVE-2026-7383.patch: reject oversized inputs before the shifts and in out_utf8() in crypto/asn1/a_mbstr.c.
  • CVE-2026-7383
• SECURITY UPDATE: Out-of-bounds read in kek_unwrap_key() check-byte validation when a CMS PasswordRecipientInfo uses a KEK cipher with a block size smaller than 4 octets, making the decrypted buffer smaller than the seven octets the check-byte test reads.
  • debian/patches/CVE-2026-9076.patch: reject blocklen < 4 and oversized inlen in kek_unwrap_key() in crypto/cms/cms_pwri.c.
  • CVE-2026-9076
• SECURITY UPDATE: Heap buffer over-read in ASN.1 content parsing: the long content length is truncated to int when asn1_d2i_ex_primitive() calls asn1_ex_c2i(), so ASN1_STRING_set() could be called with an inconsistent length.
  • debian/patches/CVE-2026-34180.patch: reject content lengths not representable as int before calling asn1_ex_c2i() in crypto/asn1/tasn_dec.c (signature kept, asn1_ex_c2i() is public API in 1.0.2).
  • CVE-2026-34180
• SECURITY UPDATE: NULL pointer dereference when processing CMS PasswordRecipientInfo with the optional keyDerivationAlgorithm field absent, allowing a denial of service via crafted CMS messages.
  • debian/patches/CVE-2026-42766.patch: fail cleanly when keyDerivationAlgorithm is missing in crypto/cms/cms_pwri.c.
  • CVE-2026-42766
• SECURITY UPDATE: Use-after-free in PKCS7_verify() where the cleanup path can free the caller-owned indata BIO via BIO_free_all() when verifying a crafted PKCS#7 structure with an empty digestAlgorithms SET, leading to crashes, heap corruption or potentially remote code execution.
  • debian/patches/CVE-2026-45447.patch: free the BIO chain explicitly, stopping at the caller-owned indata, in crypto/pkcs7/pk7_smime.c.
  • CVE-2026-45447

• SECURITY UPDATE: Heap buffer overflow in ASN1_mbstring_ncopy() where the destination length for BMPSTRING and UNIVERSALSTRING output is computed by a signed left shift that can overflow int, producing an undersized allocation followed by out-of-bounds writes for oversized attacker-controlled inputs reaching ASN1_mbstring_copy() or ASN1_mbstring_ncopy() directly.
  • debian/patches/CVE-2026-7383.patch: reject oversized inputs before the shifts and in out_utf8() in crypto/asn1/a_mbstr.c.
  • CVE-2026-7383
• SECURITY UPDATE: Out-of-bounds read in kek_unwrap_key() check-byte validation when a CMS PasswordRecipientInfo uses a KEK cipher with a block size smaller than 4 octets, making the decrypted buffer smaller than the seven octets the check-byte test reads.
  • debian/patches/CVE-2026-9076.patch: reject blocklen < 4 and oversized inlen in kek_unwrap_key() in crypto/cms/cms_pwri.c.
  • CVE-2026-9076
• SECURITY UPDATE: Heap buffer over-read in ASN.1 content parsing: the long content length was truncated to int in asn1_ex_c2i(), so ASN1_STRING_set() could be called with an inconsistent length.
  • debian/patches/CVE-2026-34180.patch: pass the length as long in asn1_ex_c2i() and reject lengths not representable as int in crypto/asn1/tasn_dec.c.
  • CVE-2026-34180
• SECURITY UPDATE: NULL pointer dereference when processing CMS PasswordRecipientInfo with the optional keyDerivationAlgorithm field absent, allowing a denial of service via crafted CMS messages.
  • debian/patches/CVE-2026-42766.patch: fail cleanly when keyDerivationAlgorithm is missing in crypto/cms/cms_pwri.c.
  • CVE-2026-42766
• SECURITY UPDATE: Use-after-free in PKCS7_verify() where the cleanup path can free the caller-owned indata BIO via BIO_free_all() when verifying a crafted PKCS#7 structure with an empty digestAlgorithms SET, leading to crashes, heap corruption or potentially remote code execution.
  • debian/patches/CVE-2026-45447.patch: free the BIO chain explicitly, stopping at the caller-owned indata, in crypto/pkcs7/pk7_smime.c.
  • debian/patches/CVE-2026-45447-test.patch: upstream regression test (empty digestAlgorithms SET must fail cleanly).
  • CVE-2026-45447

• SECURITY UPDATE: Heap buffer overflow in ASN1_mbstring_ncopy() where the destination length for BMPSTRING and UNIVERSALSTRING output is computed by a signed left shift that can overflow int, producing an undersized allocation followed by out-of-bounds writes for oversized attacker-controlled inputs reaching ASN1_mbstring_copy() or ASN1_mbstring_ncopy() directly.
  • debian/patches/CVE-2026-7383.patch: reject oversized inputs before the shifts and in out_utf8() in crypto/asn1/a_mbstr.c.
  • CVE-2026-7383
• SECURITY UPDATE: Out-of-bounds read in kek_unwrap_key() check-byte validation when a CMS PasswordRecipientInfo uses a KEK cipher with a block size smaller than 4 octets, making the decrypted buffer smaller than the seven octets the check-byte test reads.
  • debian/patches/CVE-2026-9076.patch: reject blocklen < 4 and oversized inlen in kek_unwrap_key() in crypto/cms/cms_pwri.c.
  • CVE-2026-9076
• SECURITY UPDATE: Heap buffer over-read in ASN.1 content parsing: the long content length was truncated to int in asn1_ex_c2i(), so ASN1_STRING_set() could be called with an inconsistent length.
  • debian/patches/CVE-2026-34180.patch: pass the length as long in asn1_ex_c2i() and reject lengths not representable as int in crypto/asn1/tasn_dec.c.
  • CVE-2026-34180
• SECURITY UPDATE: NULL pointer dereference when processing CMS PasswordRecipientInfo with the optional keyDerivationAlgorithm field absent, allowing a denial of service via crafted CMS messages.
  • debian/patches/CVE-2026-42766.patch: fail cleanly when keyDerivationAlgorithm is missing in crypto/cms/cms_pwri.c.
  • CVE-2026-42766

• CVE-2026-34180: fix heap buffer over-read in ASN.1 content parsing caused by truncating a long content length to int
• CVE-2026-7383: fix heap buffer overflow in ASN1_mbstring_ncopy() caused by signed integer overflow when computing the output length
• CVE-2026-42766: fix NULL pointer dereference when keyDerivationAlgorithm is absent in CMS PasswordRecipientInfo
• CVE-2026-9076: fix out-of-bounds read in kek_unwrap_key() check-byte validation for KEK ciphers with a block size below 4 octets
• CVE-2026-42768: enforce implicit rejection for CMS and PKCS#7 RSA PKCS#1 v1.5 decryption

• CVE-2026-34180: fix heap buffer over-read in ASN.1 content parsing caused by truncating a long content length to int
• CVE-2026-7383: fix heap buffer overflow in ASN1_mbstring_ncopy() caused by signed integer overflow when computing the output length
• CVE-2026-42766: fix NULL pointer dereference when keyDerivationAlgorithm is absent in CMS PasswordRecipientInfo
• CVE-2026-9076: fix out-of-bounds read in kek_unwrap_key() check-byte validation for KEK ciphers with a block size below 4 octets
• CVE-2026-42768: enforce implicit rejection for CMS and PKCS#7 RSA PKCS#1 v1.5 decryption

• CVE-2026-34180: fix heap buffer over-read in ASN.1 content parsing caused by truncating a long content length to int
• CVE-2026-7383: fix heap buffer overflow in ASN1_mbstring_ncopy() caused by signed integer overflow when computing the output length
• CVE-2026-42766: fix NULL pointer dereference when keyDerivationAlgorithm is absent in CMS PasswordRecipientInfo
• CVE-2026-9076: fix out-of-bounds read in kek_unwrap_key() check-byte validation for KEK ciphers with a block size below 4 octets
• CVE-2026-42768: enforce implicit rejection for CMS and PKCS#7 RSA PKCS#1 v1.5 decryption

• CVE-2026-7383: fix signed integer overflow when sizing Unicode output in ASN1_mbstring_ncopy()
• CVE-2026-9076: fix heap out-of-bounds read in kek_unwrap_key() check-byte validation
• CVE-2026-28388: fix NULL pointer dereference when delta CRL lacks the CRL Number extension
• CVE-2026-34180: avoid length truncation in ASN1_STRING_set() when called from asn1_ex_c2i()
• CVE-2026-42766: fix NULL dereference when keyDerivationAlgorithm is absent in CMS PasswordRecipientInfo

• CVE-2026-34180: avoid truncating a long ASN.1 content length to int in asn1_ex_c2i(), which caused a heap buffer over-read for primitive elements larger than 2GB
• CVE-2026-42766: reject a CMS PasswordRecipientInfo whose keyDerivationAlgorithm is absent instead of dereferencing NULL

• CVE-2026-34180: avoid truncating a long ASN.1 content length to int in asn1_ex_c2i(), which caused a heap buffer over-read for primitive elements larger than 2GB
• CVE-2026-42766: reject a CMS PasswordRecipientInfo whose keyDerivationAlgorithm is absent instead of dereferencing NULL

• CVE-2026-34180: avoid truncating a long ASN.1 content length to int in asn1_ex_c2i(), which caused a heap buffer over-read for primitive elements larger than 2GB
• CVE-2026-42766: reject a CMS PasswordRecipientInfo whose keyDerivationAlgorithm is absent instead of dereferencing NULL

• CVE-2026-34180: widen asn1_ex_c2i length to long and reject truncating lengths to avoid an ASN1_STRING heap buffer over-read
• CVE-2026-42766: guard against a missing CMS PasswordRecipientInfo KeyDerivationAlgorithm to prevent a NULL pointer dereference

• SECURITY UPDATE: fix ASN.1 decoder length truncation causing heap buffer over-read (tasn_dec.c)
  • debian/patches/CVE-2026-34180.patch: fix ASN.1 decoder length truncation causing heap buffer over-read (tasn_dec.c)
  • CVE-2026-34180
• SECURITY UPDATE: NULL check pwri->keyDerivationAlgorithm in cms_RecipientInfo_pwri_crypt() (cms_pwri.c)
  • debian/patches/CVE-2026-42766.patch: NULL check pwri->keyDerivationAlgorithm in cms_RecipientInfo_pwri_crypt() (cms_pwri.c)
  • CVE-2026-42766

• CVE-2026-42766: fix NULL pointer dereference during password-based CMS decryption when the optional keyDerivationAlgorithm field is absent
• CVE-2026-34180: fix heap buffer over-read caused by integer truncation of ASN.1 primitive content lengths above 2 GB on 64-bit platforms

• CVE-2026-42766: fix NULL pointer dereference during password-based CMS decryption when the optional keyDerivationAlgorithm field is absent
• CVE-2026-34180: fix heap buffer over-read caused by integer truncation of ASN.1 primitive content lengths above 2 GB on 64-bit platforms

• CVE-2026-42766: fix NULL pointer dereference during password-based CMS decryption when the optional keyDerivationAlgorithm field is absent
• CVE-2026-34180: fix heap buffer over-read caused by integer truncation of ASN.1 primitive content lengths above 2 GB on 64-bit platforms

The updated packages fix security vulnerabilities: Possible Heap Buffer Overflow in ASN.1 Multibyte String Conversion. (CVE-2026-7383) Out-of-Bounds Read in CMS Password-Based Decryption. (CVE-2026-9076) Heap Buffer Over-read in ASN.1 Content Parsing. (CVE-2026-34180) PKCS#12 Files with PBMAC1 Are Accepted with Short HMAC Keys. (CVE-2026-34181) CMS AuthEnvelopedData Processing May Accept Forged Messages. (CVE-2026-34182) Unbounded Memory Growth in the QUIC PATH_CHALLENGE Handler. (CVE-2026-34183) NULL Pointer Dereference in QUIC Server Initial Packet Handling. (CVE-2026-42764) Possible NULL Dereference in Password-Based CMS Decryption. (CVE-2026-42766) NULL Pointer Dereference in CRMF EncryptedValue Decryption. (CVE-2026-42767) Multi-RecipientInfo Bleichenbacher Oracle in CMS_decrypt() and PKCS7_decrypt(). (CVE-2026-42768) Trust-Anchor Substitution via cert/issuer Typo in CMP rootCaKeyUpdate. (CVE-2026-42769) FFC-DH Peer Validation Uses Attacker-Supplied q. (CVE-2026-42770) AES-OCB IV Ignored on EVP_Cipher() Path. (CVE-2026-45445) Incorrect Tag Processing for Empty Messages in AES-GCM-SIV and AES-SIV modes. (CVE-2026-45446) Heap Use-After-Free in the PKCS7_verify(). (CVE-2026-45447)