RUSTSEC-2026-0042: CRL Distribution Point Scope Check Logic Error in AWS-LC

What to do

1. See which version you have: cargo tree -i aws-lc-fips-sys (it also shows which of your dependencies pulls it in).
2. Update within your version requirement: cargo update -p aws-lc-fips-sys. If the fix is a newer major or minor than your requirement allows, raise it in Cargo.toml (for example aws-lc-fips-sys = "0.13.13") 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

A logic error in CRL distribution point matching in AWS-LC allows a revoked certificate to bypass revocation checks during certificate validation, when the application enables CRL checking and uses partitioned CRLs with Issuing Distribution Point (IDP) extensions.

Customers of AWS services do not need to take action. aws-lc-fips-sys contains code from AWS-LC. Applications using aws-lc-fips-sys should upgrade to the most recent release of aws-lc-fips-sys.

Workarounds

Applications can workaround this issue if they do not enable CRL checking (X509_V_FLAG_CRL_CHECK). Applications using complete (non-partitioned) CRLs without IDP extensions are also not affected.

Otherwise, there is no workaround and applications using aws-lc-fips-sys should upgrade to the most recent releases of aws-lc-fips-sys.

References

• Package: crates.io/crates/aws-lc-fips-sys
• Advisory: rustsec.org/advisories/RUSTSEC-2026-0042.html
• Web: aws.amazon.com/security/security-bulletins/2026-010-AWS
• Advisory: github.com/aws/aws-lc-rs/security/advisories/GHSA-9f94-5g5w-gf6r

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-fips-sys

• Vulnerability MediumRUSTSEC-2026-0043 · 2026-03-02Timing Side-Channel in AES-CCM Tag Verification in AWS-LC

Full security history of aws-lc-fips-sys