How severe is GHSA-9f94-5g5w-gf6r?

GHSA-9f94-5g5w-gf6r has a CVSS score of 7.4/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by GHSA-9f94-5g5w-gf6r?

GHSA-9f94-5g5w-gf6r affects the following packages: aws-lc-fips-sys (crates.io), aws-lc-sys (crates.io). Ecosystems affected: crates.io.

How do I fix GHSA-9f94-5g5w-gf6r?

Update aws-lc-fips-sys to 0.13.13 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-9f94-5g5w-gf6r is resolved across your whole dependency graph.

How do I detect GHSA-9f94-5g5w-gf6r in my crates.io dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for aws-lc-fips-sys, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate GHSA-9f94-5g5w-gf6r if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Is GHSA-9f94-5g5w-gf6r actively exploited in the wild?

No public exploit code has been indexed for GHSA-9f94-5g5w-gf6r yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for GHSA-9f94-5g5w-gf6r?

GHSA-9f94-5g5w-gf6r has an EPSS (Exploit Prediction Scoring System) score of 0.3%, placing it in the 17th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is GHSA-9f94-5g5w-gf6r?

GHSA-9f94-5g5w-gf6r is classified as CWE-299 (CWE-299). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was GHSA-9f94-5g5w-gf6r published, and has it been updated?

GHSA-9f94-5g5w-gf6r was published on March 20, 2026 and was last updated on September 10, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🦀

🦀 crates.io

Not in CISA KEV

HIGH severity

CRL Distribution Point Scope Check Logic Error in AWS-LCGHSA-9f94-5g5w-gf6r

HIGH

GHSA-9f94-5g5w-gf6r is a high-severity (CVSS 7.4) CWE-299 vulnerability in aws-lc-fips-sys. A fix is available for aws-lc-fips-sys — see the affected versions and patch details below.

Also known asCVE-2026-4428RUSTSEC-2026-0042RUSTSEC-2026-0048

Published

Mar 20, 2026

Updated

Sep 10, 2026

Affected

2 pkgs

Patched

2 / 2

Exploits

None indexed

Exploitation data as of Nov 12, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

A successful exploit gives an attacker total control of the affected component, not partial access.
CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for GHSA-9f94-5g5w-gf6r.

EPSS Exploitation Probability

via FIRST.org ↗

0.3%probability of exploitation in next 30 days

Lower Risk+0.00%

Lower risk than most CVEs17th percentile — riskier than 17% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

2 pkgs affected

🦀aws-lc-fips-sys🦀aws-lc-sys

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects crates.io packages — download data is not available via public APIs for these ecosystems.

Description

Summary

AWS-LC is an open-source, general-purpose cryptographic library.

Impact

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-sys and aws-lc-fips-sys contain code from AWS-LC. Applications using aws-lc-sys or aws-lc-fips-sys should upgrade to the most recent releases of aws-lc-sys or aws-lc-fips-sys.

Impacted versions:

aws-lc-sys >= v0.15.0, < v0.39.0
aws-lc-fips-sys >= v0.13.0, < v0.13.13

Patches

The patch is included in aws-lc-sys v0.39.0 and aws-lc-fips-sys v0.13.13.

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-sys or aws-lc-fips-sys should upgrade to the most recent releases of aws-lc-sys or aws-lc-fips-sys.

References

If you have any questions or comments about this advisory, we ask that you contact AWS Security via our vulnerability reporting page or directly via email to [email protected]. Please do not create a public GitHub issue.

Affected Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
🦀crates.io	`aws-lc-fips-sys`	≥ 0.13.0&&< 0.13.13	0.13.13`cargo update -p aws-lc-fips-sys --precise 0.13.13`
🦀crates.io	`aws-lc-sys`	≥ 0.15.0&&< 0.39.0	0.39.0`cargo update -p aws-lc-sys --precise 0.39.0`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for aws-lc-fips-sys, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update aws-lc-fips-sys to 0.13.13 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-9f94-5g5w-gf6r is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatModerate

Workaround published by Red Hat

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.

Source: Red Hat security advisory for GHSA-9f94-5g5w-gf6r (CC BY 4.0)

Frequently Asked Questions

### Summary AWS-LC is an open-source, general-purpose cryptographic library. ### Impact 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-sys and aws-lc-fips-sys contain code from AWS-LC. Applications using aws-lc-sys or aws-lc-fips-sys should upgrade to the most recent releases of aws-lc-sys or aws-lc-fips-sys. ###