GHSA-mxw3-3hh2-x2mh
HIGHRack has a Directory Traversal via Rack:Directory
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
rack💎rack💎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
Rack::Directory’s path check used a string prefix match on the expanded path. A request like /../root_example/ can escape the configured root if the target path starts with the root string, allowing directory listing outside the intended root.
Details
In directory.rb, File.expand_path(File.join(root, path_info)).start_with?(root) does not enforce a path boundary. If the server root is /var/www/root, a path like /var/www/root_backup passes the check because it shares the same prefix, so Rack::Directory will list that directory also.
Impact
Information disclosure via directory listing outside the configured root when Rack::Directory is exposed to untrusted clients and a directory shares the root prefix (e.g., public2, www_backup).
Mitigation
- Update to a patched version of Rack that correctly checks the root prefix.
- Don't name directories with the same prefix as one which is exposed via
Rack::Directory.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💎RubyGems | rack | all versions | 2.2.22 |
| 💎RubyGems | rack | ≥ 3.0.0.beta1&&< 3.1.20 | 3.1.20 |
| 💎RubyGems | rack | ≥ 3.2.0&&< 3.2.5 | 3.2.5 |
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 2.2.22 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-mxw3-3hh2-x2mh 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-mxw3-3hh2-x2mh 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-mxw3-3hh2-x2mh. 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-mxw3-3hh2-x2mh in your dependencies?
O3 detects GHSA-mxw3-3hh2-x2mh across RubyGems dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.