Rust advisories / aws-lc-fips-sys
Vulnerability MediumRUSTSEC-2026-0043 · aws-lc-fips-sys
RUSTSEC-2026-0043: Timing Side-Channel in AES-CCM Tag Verification in AWS-LC
Short answerA security vulnerability in the aws-lc-fips-sys crate: Timing Side-Channel in AES-CCM Tag Verification in AWS-LC. Medium severity (CVSS 5.9). Fixed in 0.13.12: update to a fixed version.
| Crate | aws-lc-fips-sys |
|---|---|
| Type | Vulnerability (crypto-failure) |
| Affected versions | From 0.13.0 before 0.13.12. |
| Fixed in | 0.13.12 |
| Severity | Medium, CVSS 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N |
| Published | 2026-03-02 |
| Last changed | 2026-03-21 |
| Also known as | CVE-2026-3337, GHSA-65p9-r9h6-22vj, GHSA-frmv-5gcm-jwxh, RUSTSEC-2026-0045 |
What to do
- See which version you have:
cargo tree -i aws-lc-fips-sys(it also shows which of your dependencies pulls it in). - 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 exampleaws-lc-fips-sys = "0.13.12") or update the dependency that pulls it in. - Check again with
cargo audit, or paste your Cargo.lock into our Cargo.toml checker.
Details from the advisory
Observable timing discrepancy in AES-CCM decryption in AWS-LC allows an unauthenticated user to potentially determine authentication tag validity via timing analysis.
The impacted implementations are through the EVP CIPHER API: EVP_aes_128_ccm, EVP_aes_192_ccm, and EVP_aes_256_ccm.
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
In the special cases of using AES-CCM with (M=4, L=2), (M=8, L=2), or (M=16, L=2), applications can workaround this issue by using AES-CCM through the EVP AEAD API using implementations EVP_aead_aes_128_ccm_bluetooth, EVP_aead_aes_128_ccm_bluetooth_8, and EVP_aead_aes_128_ccm_matter respectively.
Otherwise, there is no workaround and applications using aws-lc-fips-sys should upgrade to the most recent release of aws-lc-fips-sys.
References
- Package: crates.io/crates/aws-lc-fips-sys
- Advisory: rustsec.org/advisories/RUSTSEC-2026-0043.html
- Web: aws.amazon.com/security/security-bulletins/2026-005-AWS
- Advisory: github.com/aws/aws-lc-rs/security/advisories/GHSA-65p9-r9h6-22vj
From the RustSec Advisory Database (CC0-1.0) via the OSV export, downloaded Oct 24, 2026. Severity score computed from the published CVSS vector.
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