webpki: CPU denial of service in certificate path buildingGHSA-8qv2-5vq6-g2g7
HIGHFix: briansmith/webpki@30a108eGHSA-8qv2-5vq6-g2g7 is a high-severity (CVSS 7.5) vulnerability in webpki. A fix is available for webpki — see the affected versions and patch details below.
Real-World Exposure
webpkiReal-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
When this crate is given a pathological certificate chain to validate, it will spend CPU time exponential with the number of candidate certificates at each step of path building.
Both TLS clients and TLS servers that accept client certificate are affected.
This was previously reported in https://github.com/briansmith/webpki/issues/69.
rustls-webpki is a fork of this crate which contains a fix for this issue and is actively maintained.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🦀crates.io | webpki | all versions | 0.22.2cargo update -p webpki --precise 0.22.2 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for webpki, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update webpki to 0.22.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-8qv2-5vq6-g2g7 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.
Frequently Asked Questions
Is GHSA-8qv2-5vq6-g2g7 in your dependencies?
Find it across crates.io, including transitive dependencies.