CVE-2026-3336
PKCS7_verify Certificate Chain Validation Bypass in AWS-LC
Improper certificate validation in PKCS7_verify() in AWS-LC allows an unauthenticated user to bypass certificate chain verification when processing PKCS7 objects with multiple signers, except the final signer.
Customers of AWS services do not need to take action. Applications using AWS-LC should upgrade to AWS-LC version 1.69.0.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- High
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
PKCS7_verify Certificate Chain Validation Bypass in AWS-LC
Improper certificate validation in PKCS7_verify() in AWS-LC allows an unauthenticated user to bypass certificate chain verification when processing PKCS7 objects with multiple signers, except the final signer.
Customers of AWS services do not need to take action. Applications using AWS-LC should upgrade to AWS-LC version 1.69.0.
- Record
CVE-2026-3336- CVSS 4.0
- 8.7 High
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N - CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N - CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N - Weakness
- CWE-295, CWE-295
- Updated
- 2026-11-02
EUVDEUVD-2026-9264
Improper certificate validation in PKCS7_verify() in AWS-LC allows an unauthenticated user to bypass certificate chain verification when processing PKCS7 objects with multiple signers, except the final signer.
Customers of AWS services do not need to take action. Applications using AWS-LC should upgrade to AWS-LC version 1.69.0.
- Record
EUVD-2026-9264- CVSS 4.0
- 8.7 High
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-vw5v-4f2q-w9xf
AWS-LC has PKCS7_verify Certificate Chain Validation Bypass
Summary
AWS-LC is an open-source, general-purpose cryptographic library.
Impact
Improper certificate validation in PKCS7_verify() in AWS-LC allows an unauthenticated user to bypass certificate chain verification when processing PKCS7 objects with multiple signers, except the final signer.
Customers of AWS services do not need to take action. aws-lc-sys contains code from AWS-LC. Applications using aws-lc-sys should upgrade to the most recent release of aws-lc-sys.
Impacted versions:
aws-lc-sys versions: >= 0.24.0, < 0.38.0
Patches
The patch is included in v0.38.0
Workarounds
There is no workaround. Applications using aws-lc-sys should upgrade to the most recent release of aws-lc-sys.
Resources
If there are any questions or comments about this advisory, contact [AWS/Amazon] Security via the vulnerability reporting page or directly via email to [email protected]. Please do not create a public GitHub issue.
Acknowledgement
AWS-LC would like to thank Joshua Rogers (https://joshua.hu/) for collaborating on this issue through the coordinated vulnerability disclosure process.
- Record
GHSA-vw5v-4f2q-w9xf- CVSS 4.0
- 8.7 High
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N - CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N - Weakness
- CWE-295
- Updated
- 2026-11-02
NVD
Improper certificate validation in PKCS7_verify() in AWS-LC allows an unauthenticated user to bypass certificate chain verification when processing PKCS7 objects with multiple signers, except the final signer.
Customers of AWS services do not need to take action. Applications using AWS-LC should upgrade to AWS-LC version 1.69.0.
- Record
CVE-2026-3336- CVSS 4.0
- 8.7 High
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N - Weakness
- CWE-295
- Updated
- 2026-11-02
OSV
PKCS7_verify Certificate Chain Validation Bypass in AWS-LC
Improper certificate validation in PKCS7_verify() in AWS-LC allows an unauthenticated user to bypass certificate chain verification when processing PKCS7 objects with multiple signers, except the final signer.
Customers of AWS services do not need to take action. Applications using AWS-LC should upgrade to AWS-LC version 1.69.0.
- Record
CVE-2026-3336- CVSS 4.0
- 8.7 High
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N - Weakness
- CWE-295
- Updated
- 2026-11-02
OSVGHSA-vw5v-4f2q-w9xf
AWS-LC has PKCS7_verify Certificate Chain Validation Bypass
Summary
AWS-LC is an open-source, general-purpose cryptographic library.
Impact
Improper certificate validation in PKCS7_verify() in AWS-LC allows an unauthenticated user to bypass certificate chain verification when processing PKCS7 objects with multiple signers, except the final signer.
Customers of AWS services do not need to take action. aws-lc-sys contains code from AWS-LC. Applications using aws-lc-sys should upgrade to the most recent release of aws-lc-sys.
Impacted versions:
aws-lc-sys versions: >= 0.24.0, < 0.38.0
Patches
The patch is included in v0.38.0
Workarounds
There is no workaround. Applications using aws-lc-sys should upgrade to the most recent release of aws-lc-sys.
Resources
If there are any questions or comments about this advisory, contact [AWS/Amazon] Security via the vulnerability reporting page or directly via email to [email protected]. Please do not create a public GitHub issue.
Acknowledgement
AWS-LC would like to thank Joshua Rogers (https://joshua.hu/) for collaborating on this issue through the coordinated vulnerability disclosure process.
- Record
GHSA-vw5v-4f2q-w9xf- CVSS 4.0
- 8.7 High
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N - CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N - Weakness
- CWE-295
- Updated
- 2026-11-02
OSVRUSTSEC-2026-0046
PKCS7_verify Certificate Chain Validation Bypass in AWS-LC
Improper certificate validation in PKCS7_verify() in AWS-LC allows an
unauthenticated user to bypass certificate chain verification when processing
PKCS7 objects with multiple signers, except the final signer.
Customers of AWS services do not need to take action. aws-lc-sys contains
code from AWS-LC. Applications using aws-lc-sys should upgrade to the most
recent release of aws-lc-sys.
There is no workaround; applications using aws-lc-sys should upgrade to the
most recent release of aws-lc-sys.
- Record
RUSTSEC-2026-0046- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N - Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
aws-lc-syscrates.io |
0.24.0 up to 0.38.0 | 0.38.0 |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-3336 is a high vulnerability (CVSS 8.7) in Aws Aws-lc, published March 2, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.74%, the 54th percentile. Fixed in aws-lc-sys 0.38.0.
References
aws.amazon.com/security/security-bulletins/2026-005-AWS
github.com/aws/aws-lc/releases/tag/v1.69.0
access.redhat.com/security/cve/CVE-2026-3336
bugzilla.redhat.com/show_bug.cgi?id=2444026
security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-3336.json
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nvd.nist.gov/vuln/detail/CVE-2026-3336
rustsec.org/advisories/RUSTSEC-2026-0046.html
crates.io/crates/aws-lc-sys