CVE-2026-45446

Issue summary: The implementations of AES-SIV (RFC 5297) and AES-GCM-SIV (RFC 8452) mishandle the authentication of AAD (Additional Authenticated Data) with an empty ciphertext allowing a forgery of such messages.

Impact summary: An attacker can forge empty messages with arbitrary AAD to the victim's application using these ciphers.

AES-SIV (RFC 5297) and AES-GCM-SIV (RFC 8452) are nonce-misuse-resistant AEAD modes: they accept a key, nonce, optional AAD (bytes that are authenticated but not encrypted), and plaintext, and produces ciphertext plus a 16-byte tag. On decrypt, EVP_DecryptFinal_ex() is documented to return success only if the tag is verified succesfully.

In OpenSSL's provider implementation of these ciphers, the expected tag is computed only when decryption function is invoked with non-empty data. If the caller supplies AAD and then calls EVP_DecryptFinal_ex() without invocation of the ciphertext update, which can happen when the received ciphertext length is zero, the tag is never recalculated and still holds its all-zeros value.

When AES-GCM-SIV is used, an attacker who sends arbitrary AAD, empty ciphertext, and all-zeros tag passes authentication under any key they do not know, single-shot. When AES-SIV is used, for mounting the attack it's necessary for the application to reuse the decryption context without resetting the key.

AES-SIV is implemented since OpenSSL 3.0. AES-GCM-SIV is implemented since OpenSSL 3.2.

No protocols implemented in OpenSSL itself (TLS/CMS/PKCS7/HPKE/QUIC) support either AES-GCM-SIV or AES-SIV. To mount an attack, the applications must implement their own protocol and use the EVP interface. Also they must skip the ciphertext update when a message with an empty ciphertext arrives.

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

Issue summary: The implementations of AES-SIV (RFC 5297) and AES-GCM-SIV (RFC 8452) mishandle the authentication of AAD (Additional Authenticated Data) with an empty ciphertext allowing a forgery of such messages. Impact summary: An attacker can forge empty messages with arbitrary AAD to the victim's application using these ciphers. AES-SIV (RFC 5297) and AES-GCM-SIV (RFC 8452) are nonce-misuse-resistant AEAD modes: they accept a key, nonce, optional AAD (bytes that are authenticated but not encrypted), and plaintext, and produces ciphertext plus a 16-byte tag. On decrypt, EVP_DecryptFinal_ex() is documented to return success only if the tag is verified succesfully. In OpenSSL's provider implementation of these ciphers, the expected tag is computed only when decryption function is invoked with non-empty data. If the caller supplies AAD and then calls EVP_DecryptFinal_ex() without invocation of the ciphertext update, which can happen when the received ciphertext length is zero, the tag is never recalculated and still holds its all-zeros value. When AES-GCM-SIV is used, an attacker who sends arbitrary AAD, empty ciphertext, and all-zeros tag passes authentication under any key they do not know, single-shot. When AES-SIV is used, for mounting the attack it's necessary for the application to reuse the decryption context without resetting the key. AES-SIV is implemented since OpenSSL 3.0. AES-GCM-SIV is implemented since OpenSSL 3.2. No protocols implemented in OpenSSL itself (TLS/CMS/PKCS7/HPKE/QUIC) support either AES-GCM-SIV or AES-SIV. To mount an attack, the applications must implement their own protocol and use the EVP interface. Also they must skip the ciphertext update when a message with an empty ciphertext arrives. The FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are not affected by this issue, as these algorithms are not FIPS approved and the affected code is outside the OpenSSL FIPS module boundary.

Issue summary: The implementations of AES-SIV (RFC 5297) and AES-GCM-SIV (RFC 8452) mishandle the authentication of AAD (Additional Authenticated Data) with an empty ciphertext allowing a forgery of such messages.

Impact summary: An attacker can forge empty messages with arbitrary AAD to the victim's application using these ciphers.

AES-SIV (RFC 5297) and AES-GCM-SIV (RFC 8452) are nonce-misuse-resistant AEAD modes: they accept a key, nonce, optional AAD (bytes that are authenticated but not encrypted), and plaintext, and produces ciphertext plus a 16-byte tag. On decrypt, EVP_DecryptFinal_ex() is documented to return success only if the tag is verified succesfully.

In OpenSSL's provider implementation of these ciphers, the expected tag is computed only when decryption function is invoked with non-empty data. If the caller supplies AAD and then calls EVP_DecryptFinal_ex() without invocation of the ciphertext update, which can happen when the received ciphertext length is zero, the tag is never recalculated and still holds its all-zeros value.

When AES-GCM-SIV is used, an attacker who sends arbitrary AAD, empty ciphertext, and all-zeros tag passes authentication under any key they do not know, single-shot. When AES-SIV is used, for mounting the attack it's necessary for the application to reuse the decryption context without resetting the key.

AES-SIV is implemented since OpenSSL 3.0. AES-GCM-SIV is implemented since OpenSSL 3.2.

No protocols implemented in OpenSSL itself (TLS/CMS/PKCS7/HPKE/QUIC) support either AES-GCM-SIV or AES-SIV. To mount an attack, the applications must implement their own protocol and use the EVP interface. Also they must skip the ciphertext update when a message with an empty ciphertext arrives.

The FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are not affected by this issue, as these algorithms are not FIPS approved and 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: 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 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: The implementations of AES-SIV (RFC 5297) and AES-GCM-SIV (RFC 8452) mishandle the authentication of AAD (Additional Authenticated Data) with an empty ciphertext allowing a forgery of such messages. Impact summary: An attacker can forge empty messages with arbitrary AAD to the victim's application using these ciphers. AES-SIV (RFC 5297) and AES-GCM-SIV (RFC 8452) are nonce-misuse-resistant AEAD modes: they accept a key, nonce, optional AAD (bytes that are authenticated but not encrypted), and plaintext, and produces ciphertext plus a 16-byte tag. On decrypt, EVP_DecryptFinal_ex() is documented to return success only if the tag is verified succesfully. In OpenSSL's provider implementation of these ciphers, the expected tag is computed only when decryption function is invoked with non-empty data. If the caller supplies AAD and then calls EVP_DecryptFinal_ex() without invocation of the ciphertext update, which can happen when the received ciphertext length is zero, the tag is never recalculated and still holds its all-zeros value. When AES-GCM-SIV is used, an attacker who sends arbitrary AAD, empty ciphertext, and all-zeros tag passes authentication under any key they do not know, single-shot. When AES-SIV is used, for mounting the attack it's necessary for the application to reuse the decryption context without resetting the key. AES-SIV is implemented since OpenSSL 3.0. AES-GCM-SIV is implemented since OpenSSL 3.2. No protocols implemented in OpenSSL itself (TLS/CMS/PKCS7/HPKE/QUIC) support either AES-GCM-SIV or AES-SIV. To mount an attack, the applications must implement their own protocol and use the EVP interface. Also they must skip the ciphertext update when a message with an empty ciphertext arrives. The FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are not affected by this issue, as these algorithms are not FIPS approved and 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: The implementations of AES-SIV (RFC 5297) and AES-GCM-SIV (RFC 8452) mishandle the authentication of AAD (Additional Authenticated Data) with an empty ciphertext allowing a forgery of such messages.

Impact summary: An attacker can forge empty messages with arbitrary AAD to the victim's application using these ciphers.

AES-SIV (RFC 5297) and AES-GCM-SIV (RFC 8452) are nonce-misuse-resistant AEAD modes: they accept a key, nonce, optional AAD (bytes that are authenticated but not encrypted), and plaintext, and produces ciphertext plus a 16-byte tag. On decrypt, EVP_DecryptFinal_ex() is documented to return success only if the tag is verified succesfully.

In OpenSSL's provider implementation of these ciphers, the expected tag is computed only when decryption function is invoked with non-empty data. If the caller supplies AAD and then calls EVP_DecryptFinal_ex() without invocation of the ciphertext update, which can happen when the received ciphertext length is zero, the tag is never recalculated and still holds its all-zeros value.

When AES-GCM-SIV is used, an attacker who sends arbitrary AAD, empty ciphertext, and all-zeros tag passes authentication under any key they do not know, single-shot. When AES-SIV is used, for mounting the attack it's necessary for the application to reuse the decryption context without resetting the key.

AES-SIV is implemented since OpenSSL 3.0. AES-GCM-SIV is implemented since OpenSSL 3.2.

No protocols implemented in OpenSSL itself (TLS/CMS/PKCS7/HPKE/QUIC) support either AES-GCM-SIV or AES-SIV. To mount an attack, the applications must implement their own protocol and use the EVP interface. Also they must skip the ciphertext update when a message with an empty ciphertext arrives.

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

Issue summary: The implementations of AES-SIV (RFC 5297) and AES-GCM-SIV (RFC 8452) mishandle the authentication of AAD (Additional Authenticated Data) with an empty ciphertext allowing a forgery of such messages.

Impact summary: An attacker can forge empty messages with arbitrary AAD to the victim's application using these ciphers.

AES-SIV (RFC 5297) and AES-GCM-SIV (RFC 8452) are nonce-misuse-resistant AEAD modes: they accept a key, nonce, optional AAD (bytes that are authenticated but not encrypted), and plaintext, and produces ciphertext plus a 16-byte tag. On decrypt, EVP_DecryptFinal_ex() is documented to return success only if the tag is verified succesfully.

In OpenSSL's provider implementation of these ciphers, the expected tag is computed only when decryption function is invoked with non-empty data. If the caller supplies AAD and then calls EVP_DecryptFinal_ex() without invocation of the ciphertext update, which can happen when the received ciphertext length is zero, the tag is never recalculated and still holds its all-zeros value.

When AES-GCM-SIV is used, an attacker who sends arbitrary AAD, empty ciphertext, and all-zeros tag passes authentication under any key they do not know, single-shot. When AES-SIV is used, for mounting the attack it's necessary for the application to reuse the decryption context without resetting the key.

AES-SIV is implemented since OpenSSL 3.0. AES-GCM-SIV is implemented since OpenSSL 3.2.

No protocols implemented in OpenSSL itself (TLS/CMS/PKCS7/HPKE/QUIC) support either AES-GCM-SIV or AES-SIV. To mount an attack, the applications must implement their own protocol and use the EVP interface. Also they must skip the ciphertext update when a message with an empty ciphertext arrives.

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

• CVE-2026-45446: reset AES-SIV final_ret on context reuse so a forged all-zero tag is not accepted for empty-ciphertext messages
• CVE-2026-9076: reject KEK ciphers with block size below 4 in CMS kek_unwrap_key to prevent an out-of-bounds read during check-byte validation

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)

These are all security issues fixed in the libopenssl-3-devel-3.5.3-6.1 package on the GA media of openSUSE Tumbleweed.

This update for openssl-3 fixes the following issues

• CVE-2026-2673: TLS 1.3 servers may choose unexpected key agreement group (bsc#1259652).
• CVE-2026-7383: Possible Heap Buffer Overflow in ASN.1 Multibyte String Conversion (bsc#1266340).
• CVE-2026-9076: Out-of-Bounds Read in CMS Password-Based Decryption (bsc#1266341).
• CVE-2026-34180: Heap Buffer Over-read in ASN.1 Content Parsing (bsc#1266342).
• CVE-2026-34182: CMS AuthEnvelopedData Processing May Accept Forged Messages (bsc#1266344).
• CVE-2026-34183: Unbounded Memory Growth in the QUIC PATH_CHALLENGE Handler (bsc#1266345).
• CVE-2026-42764: NULL pointer dereference in QUIC server initial packet handling (bsc#1266347).
• CVE-2026-42766: Possible NULL Dereference in Password-Based CMS Decryption (bsc#1266349).
• CVE-2026-42767: NULL Pointer Dereference in CRMF EncryptedValue Decryption (bsc#1266350).
• CVE-2026-42768: Multi-RecipientInfo Bleichenbacher Oracle in CMS_decrypt() and PKCS7_decrypt() (bsc#1266351).
• CVE-2026-42769: Trust-Anchor Substitution via cert/issuer Typo in CMP rootCaKeyUpdate (bsc#1266352).
• CVE-2026-42770: FFC-DH Peer Validation Uses Attacker-Supplied q (bsc#1266353).
• CVE-2026-45445: AES-OCB IV Ignored on EVP_Cipher() Path (bsc#1266355).
• CVE-2026-45446: Incorrect Tag Processing for Empty Messages in AES-GCM-SIV and AES-SIV modes (bsc#1266356).
• CVE-2026-45447: Heap Use-After-Free in OpenSSL PKCS7_verify() (bsc#1266357).

This update for openssl-3 fixes the following issues

• CVE-2026-7383: Possible Heap Buffer Overflow in ASN.1 Multibyte String Conversion (bsc#1266340).
• CVE-2026-9076: Out-of-Bounds Read in CMS Password-Based Decryption (bsc#1266341).
• CVE-2026-34180: Heap Buffer Over-read in ASN.1 Content Parsing (bsc#1266342).
• CVE-2026-34182: CMS AuthEnvelopedData Processing May Accept Forged Messages (bsc#1266344).
• CVE-2026-42766: Possible NULL Dereference in Password-Based CMS Decryption (bsc#1266349).
• CVE-2026-42770: FFC-DH Peer Validation Uses Attacker-Supplied q (bsc#1266353).
• CVE-2026-45445: AES-OCB IV Ignored on EVP_Cipher() Path (bsc#1266355).
• CVE-2026-45446: Incorrect Tag Processing for Empty Messages in AES-GCM-SIV and AES-SIV modes (bsc#1266356).
• CVE-2026-45447: Heap Use-After-Free in OpenSSL PKCS7_verify() (bsc#1266357).

This update for openssl-3 fixes the following issues

• CVE-2024-41996: DHEATATTACK: Validating the order of the public keys in the Diffie-Hellman Key Agreement Protocol, when an approved safe prime is used, allows remote attackers to trigger expensive server-side DHE (bsc#1230698).
• CVE-2026-7383: Possible Heap Buffer Overflow in ASN.1 Multibyte String Conversion (bsc#1266340).
• CVE-2026-9076: Out-of-Bounds Read in CMS Password-Based Decryption (bsc#1266341).
• CVE-2026-28390: NULL pointer dereference during processing of a crafted CMS EnvelopedData message with KeyTransportRecipientInfo (bsc#1261678).
• CVE-2026-34180: Heap Buffer Over-read in ASN.1 Content Parsing (bsc#1266342).
• CVE-2026-34182: CMS AuthEnvelopedData Processing May Accept Forged Messages (bsc#1266344).
• CVE-2026-42766: Possible NULL Dereference in Password-Based CMS Decryption (bsc#1266349).
• CVE-2026-42770: FFC-DH Peer Validation Uses Attacker-Supplied q (bsc#1266353).
• CVE-2026-45445: AES-OCB IV Ignored on EVP_Cipher() Path (bsc#1266355).
• CVE-2026-45446: Incorrect Tag Processing for Empty Messages in AES-GCM-SIV and AES-SIV modes (bsc#1266356).
• CVE-2026-45447: Heap Use-After-Free in OpenSSL PKCS7_verify() (bsc#1266357).

This update for openssl-3 fixes the following issues

• CVE-2026-2673: TLS 1.3 servers may choose unexpected key agreement group (bsc#1259652).
• CVE-2026-7383: Possible Heap Buffer Overflow in ASN.1 Multibyte String Conversion (bsc#1266340).
• CVE-2026-9076: Out-of-Bounds Read in CMS Password-Based Decryption (bsc#1266341).
• CVE-2026-34180: Heap Buffer Over-read in ASN.1 Content Parsing (bsc#1266342).
• CVE-2026-34182: CMS AuthEnvelopedData Processing May Accept Forged Messages (bsc#1266344).
• CVE-2026-34183: Unbounded Memory Growth in the QUIC PATH_CHALLENGE Handler (bsc#1266345).
• CVE-2026-42764: NULL pointer dereference in QUIC server initial packet handling (bsc#1266347).
• CVE-2026-42766: Possible NULL Dereference in Password-Based CMS Decryption (bsc#1266349).
• CVE-2026-42767: NULL Pointer Dereference in CRMF EncryptedValue Decryption (bsc#1266350).
• CVE-2026-42768: Multi-RecipientInfo Bleichenbacher Oracle in CMS_decrypt() and PKCS7_decrypt() (bsc#1266351).
• CVE-2026-42769: Trust-Anchor Substitution via cert/issuer Typo in CMP rootCaKeyUpdate (bsc#1266352).
• CVE-2026-42770: FFC-DH Peer Validation Uses Attacker-Supplied q (bsc#1266353).
• CVE-2026-45445: AES-OCB IV Ignored on EVP_Cipher() Path (bsc#1266355).
• CVE-2026-45446: Incorrect Tag Processing for Empty Messages in AES-GCM-SIV and AES-SIV modes (bsc#1266356).
• CVE-2026-45447: Heap Use-After-Free in OpenSSL PKCS7_verify() (bsc#1266357).

This update for openssl-3 fixes the following issues

• CVE-2026-2673: TLS 1.3 servers may choose unexpected key agreement group (bsc#1259652).
• CVE-2026-7383: Possible Heap Buffer Overflow in ASN.1 Multibyte String Conversion (bsc#1266340).
• CVE-2026-9076: Out-of-Bounds Read in CMS Password-Based Decryption (bsc#1266341).
• CVE-2026-34180: Heap Buffer Over-read in ASN.1 Content Parsing (bsc#1266342).
• CVE-2026-34182: CMS AuthEnvelopedData Processing May Accept Forged Messages (bsc#1266344).
• CVE-2026-34183: Unbounded Memory Growth in the QUIC PATH_CHALLENGE Handler (bsc#1266345).
• CVE-2026-42764: NULL pointer dereference in QUIC server initial packet handling (bsc#1266347).
• CVE-2026-42766: Possible NULL Dereference in Password-Based CMS Decryption (bsc#1266349).
• CVE-2026-42767: NULL Pointer Dereference in CRMF EncryptedValue Decryption (bsc#1266350).
• CVE-2026-42768: Multi-RecipientInfo Bleichenbacher Oracle in CMS_decrypt() and PKCS7_decrypt() (bsc#1266351).
• CVE-2026-42769: Trust-Anchor Substitution via cert/issuer Typo in CMP rootCaKeyUpdate (bsc#1266352).
• CVE-2026-42770: FFC-DH Peer Validation Uses Attacker-Supplied q (bsc#1266353).
• CVE-2026-45445: AES-OCB IV Ignored on EVP_Cipher() Path (bsc#1266355).
• CVE-2026-45446: Incorrect Tag Processing for Empty Messages in AES-GCM-SIV and AES-SIV modes (bsc#1266356).
• CVE-2026-45447: Heap Use-After-Free in OpenSSL PKCS7_verify() (bsc#1266357).

This update for openssl-3 fixes the following issues

• CVE-2026-7383: Possible Heap Buffer Overflow in ASN.1 Multibyte String Conversion (bsc#1266340).
• CVE-2026-9076: Out-of-Bounds Read in CMS Password-Based Decryption (bsc#1266341).
• CVE-2026-34180: Heap Buffer Over-read in ASN.1 Content Parsing (bsc#1266342).
• CVE-2026-34182: CMS AuthEnvelopedData Processing May Accept Forged Messages (bsc#1266344).
• CVE-2026-42766: Possible NULL Dereference in Password-Based CMS Decryption (bsc#1266349).
• CVE-2026-42770: FFC-DH Peer Validation Uses Attacker-Supplied q (bsc#1266353).
• CVE-2026-45445: AES-OCB IV Ignored on EVP_Cipher() Path (bsc#1266355).
• CVE-2026-45446: Incorrect Tag Processing for Empty Messages in AES-GCM-SIV and AES-SIV modes (bsc#1266356).
• CVE-2026-45447: Heap Use-After-Free in OpenSSL PKCS7_verify() (bsc#1266357).

This update for openssl-3 fixes the following issues

• CVE-2026-7383: Possible Heap Buffer Overflow in ASN.1 Multibyte String Conversion (bsc#1266340).
• CVE-2026-9076: Out-of-Bounds Read in CMS Password-Based Decryption (bsc#1266341).
• CVE-2026-34180: Heap Buffer Over-read in ASN.1 Content Parsing (bsc#1266342).
• CVE-2026-42766: Possible NULL Dereference in Password-Based CMS Decryption (bsc#1266349).
• CVE-2026-42770: FFC-DH Peer Validation Uses Attacker-Supplied q (bsc#1266353).
• CVE-2026-45445: AES-OCB IV Ignored on EVP_Cipher() Path (bsc#1266355).
• CVE-2026-45446: Incorrect Tag Processing for Empty Messages in AES-GCM-SIV and AES-SIV modes (bsc#1266356).
• CVE-2026-45447: Heap Use-After-Free in OpenSSL PKCS7_verify() (bsc#1266357).

This update for openssl-3 fixes the following issues

• CVE-2026-7383: Possible Heap Buffer Overflow in ASN.1 Multibyte String Conversion (bsc#1266340).
• CVE-2026-9076: Out-of-Bounds Read in CMS Password-Based Decryption (bsc#1266341).
• CVE-2026-34180: Heap Buffer Over-read in ASN.1 Content Parsing (bsc#1266342).
• CVE-2026-42766: Possible NULL Dereference in Password-Based CMS Decryption (bsc#1266349).
• CVE-2026-42770: FFC-DH Peer Validation Uses Attacker-Supplied q (bsc#1266353).
• CVE-2026-45445: AES-OCB IV Ignored on EVP_Cipher() Path (bsc#1266355).
• CVE-2026-45446: Incorrect Tag Processing for Empty Messages in AES-GCM-SIV and AES-SIV modes (bsc#1266356).
• CVE-2026-45447: Heap Use-After-Free in OpenSSL PKCS7_verify() (bsc#1266357).

This update for openssl-3 fixes the following issues

• CVE-2026-7383: Possible Heap Buffer Overflow in ASN.1 Multibyte String Conversion (bsc#1266340).
• CVE-2026-9076: Out-of-Bounds Read in CMS Password-Based Decryption (bsc#1266341).
• CVE-2026-34180: Heap Buffer Over-read in ASN.1 Content Parsing (bsc#1266342).
• CVE-2026-34181: PKCS#12 Files with PBMAC1 Are Accepted with Short HMAC Keys (bsc#1266343).
• CVE-2026-34183: Unbounded Memory Growth in the QUIC PATH_CHALLENGE Handler (bsc#1266345).
• CVE-2026-42766: Possible NULL Dereference in Password-Based CMS Decryption (bsc#1266349).
• CVE-2026-42767: NULL Pointer Dereference in CRMF EncryptedValue Decryption (bsc#1266350).
• CVE-2026-42768: Multi-RecipientInfo Bleichenbacher Oracle in CMS_decrypt() and PKCS7_decrypt() (bsc#1266351).
• CVE-2026-42769: Trust-Anchor Substitution via cert/issuer Typo in CMP rootCaKeyUpdate (bsc#1266352).
• CVE-2026-42770: FFC-DH Peer Validation Uses Attacker-Supplied q (bsc#1266353).
• CVE-2026-45445: AES-OCB IV Ignored on EVP_Cipher() Path (bsc#1266355).
• CVE-2026-45446: Incorrect Tag Processing for Empty Messages in AES-GCM-SIV and AES-SIV modes (bsc#1266356).
• CVE-2026-45447: Heap Use-After-Free in OpenSSL PKCS7_verify() (bsc#1266357).