GHSA-vw5v-4f2q-w9xf — aws-lc-sys
HIGHGHSA-vw5v-4f2q-w9xf is a high-severity (CVSS 7.5) CWE-295 vulnerability in aws-lc-sys. A fix is available for aws-lc-sys — see the affected versions and patch details below.
AWS-LC has PKCS7_verify Certificate Chain Validation Bypass
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- 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-vw5v-4f2q-w9xf.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
GHSA-vw5v-4f2q-w9xf plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,166 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
aws-lc-sysReal-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
Improper certificate validation in PKCS7_verify() in AWS-LC allows an unauthenticated user to bypass certificate chain verification when processing PKCS7 objects with multiple signers, except the final signer.
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.
Acknowledgement
AWS-LC would like to thank Joshua Rogers (https://joshua.hu/) for collaborating on this issue through the coordinated vulnerability disclosure process.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🦀crates.io | aws-lc-sys | ≥ 0.24.0&&< 0.38.0 | 0.38.0cargo update -p aws-lc-sys --precise 0.38.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for aws-lc-sys, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update aws-lc-sys to 0.38.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-vw5v-4f2q-w9xf 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.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-vw5v-4f2q-w9xf can be triaged on real exposure rather than presence alone.
Tailored to GHSA-vw5v-4f2q-w9xf. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
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.
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat Trusted Artifact Signer 1.3 | rhtas/tuffer-rhel9:1773307309 | RHSA-2026:5459 |
Frequently Asked Questions
Is GHSA-vw5v-4f2q-w9xf in your dependencies?
O3 Security finds GHSA-vw5v-4f2q-w9xf across crates.io dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.