GHSA-cj83-2ww7-mvq7
MEDIUMRack ReDoS Vulnerability in HTTP Accept Headers Parsing
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.
Blast Radius
rackReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects RubyGems packages — download data is not available via public APIs for these ecosystems.
Description
Summary
A Regular Expression Denial of Service (ReDoS) vulnerability exists in the Rack::Request::Helpers module when parsing HTTP Accept headers. This vulnerability can be exploited by an attacker sending specially crafted Accept-Encoding or Accept-Language headers, causing the server to spend excessive time processing the request and leading to a Denial of Service (DoS).
Details
The fix for https://github.com/rack/rack/security/advisories/GHSA-54rr-7fvw-6x8f was not applied to the main branch and thus while the issue was fixed for the Rack v3.0 release series, it was not fixed in the v3.1 release series until v3.1.5.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💎RubyGems | rack | ≥ 3.1.0&&< 3.1.5 | 3.1.5 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for rack. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update rack to 3.1.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-cj83-2ww7-mvq7 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 pinpoints whether GHSA-cj83-2ww7-mvq7 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-cj83-2ww7-mvq7. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-cj83-2ww7-mvq7 in your dependencies?
O3 detects GHSA-cj83-2ww7-mvq7 across RubyGems dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.