CVE-2026-3338
PKCS7_verify Signature Validation Bypass in AWS-LC
Improper signature validation in PKCS7_verify() in AWS-LC allows an unauthenticated user to bypass signature verification when processing PKCS7 objects with Authenticated Attributes.
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 Signature Validation Bypass in AWS-LC
Improper signature validation in PKCS7_verify() in AWS-LC allows an unauthenticated user to bypass signature verification when processing PKCS7 objects with Authenticated Attributes.
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-2026-3338- 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-347, CWE-347
- Updated
- 2026-11-02
EUVDEUVD-2026-9266
Improper signature validation in PKCS7_verify() in AWS-LC allows an unauthenticated user to bypass signature verification when processing PKCS7 objects with Authenticated Attributes.
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-2026-9266- 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-hfpc-8r3f-gw53
AWS-LC has PKCS7_verify Signature Validation Bypass
Summary
AWS-LC is an open-source, general-purpose cryptographic library.
Impact
Improper signature validation in PKCS7_verify() in AWS-LC allows an unauthenticated user to bypass signature verification when processing PKCS7 objects with Authenticated Attributes.
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.
- Record
GHSA-hfpc-8r3f-gw53- 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-347
- Updated
- 2026-11-02
NVD
Improper signature validation in PKCS7_verify() in AWS-LC allows an unauthenticated user to bypass signature verification when processing PKCS7 objects with Authenticated Attributes.
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-2026-3338- 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-347
- Updated
- 2026-11-02
OSV
PKCS7_verify Signature Validation Bypass in AWS-LC
Improper signature validation in PKCS7_verify() in AWS-LC allows an unauthenticated user to bypass signature verification when processing PKCS7 objects with Authenticated Attributes.
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-2026-3338- 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-347
- Updated
- 2026-11-02
OSVGHSA-hfpc-8r3f-gw53
AWS-LC has PKCS7_verify Signature Validation Bypass
Summary
AWS-LC is an open-source, general-purpose cryptographic library.
Impact
Improper signature validation in PKCS7_verify() in AWS-LC allows an unauthenticated user to bypass signature verification when processing PKCS7 objects with Authenticated Attributes.
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.
- Record
GHSA-hfpc-8r3f-gw53- 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-347
- Updated
- 2026-11-02
OSVRUSTSEC-2026-0047
PKCS7_verify Signature Validation Bypass in AWS-LC
Improper signature validation in PKCS7_verify() in AWS-LC allows an
unauthenticated user to bypass signature verification when processing PKCS7
objects with Authenticated Attributes.
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-2026-0047- 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-2026-3338 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 0.78%, the 56th 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-2026-3338
bugzilla.redhat.com/show_bug.cgi?id=2444025
security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-3338.json
Show 8 moreShow less
nvd.nist.gov/vuln/detail/CVE-2026-3338
rustsec.org/advisories/RUSTSEC-2026-0047.html
crates.io/crates/aws-lc-sys