RUSTSEC-2026-0047: PKCS7_verify Signature Validation Bypass in AWS-LC

What to do

1. See which version you have: cargo tree -i aws-lc-sys (it also shows which of your dependencies pulls it in).
2. Update within your version requirement: cargo update -p aws-lc-sys. If the fix is a newer major or minor than your requirement allows, raise it in Cargo.toml (for example aws-lc-sys = "0.38.0") or update the dependency that pulls it in.
3. Check again with cargo audit, or paste your Cargo.lock into our Cargo.toml checker.

Details from the advisory

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.

References

• Package: crates.io/crates/aws-lc-sys
• Advisory: rustsec.org/advisories/RUSTSEC-2026-0047.html
• Web: aws.amazon.com/security/security-bulletins/2026-005-AWS
• Advisory: github.com/aws/aws-lc-rs/security/advisories/GHSA-hfpc-8r3f-gw53

From the RustSec Advisory Database (CC0-1.0) via the OSV export, downloaded Oct 24, 2026. Severity score computed from the published CVSS vector.

Other advisories for aws-lc-sys

• VulnerabilityRUSTSEC-2026-0044 · 2026-03-19AWS-LC X.509 Name Constraints Bypass via Wildcard/Unicode CN
• Vulnerability MediumRUSTSEC-2026-0045 · 2026-03-02Timing Side-Channel in AES-CCM Tag Verification in AWS-LC
• Vulnerability HighRUSTSEC-2026-0046 · 2026-03-02PKCS7_verify Certificate Chain Validation Bypass in AWS-LC
• Vulnerability HighRUSTSEC-2026-0048 · 2026-03-19CRL Distribution Point Scope Check Logic Error in AWS-LC

Full security history of aws-lc-sys