GHSA-mq35-wqvf-r23c is a medium-severity (CVSS 6.1) Cross-site Scripting (XSS) vulnerability in sinatra. 1 public exploit reference exists, so weaponization risk is real. O3 Security confirms whether GHSA-mq35-wqvf-r23c is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Sinatra Cross-site Scripting vulnerability
Real-World Exposure
sinatraReal-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
Sinatra before 2.0.2 has XSS via the 400 Bad Request page that occurs upon a params parser exception.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💎RubyGems | sinatra | ≥ 2.0.0&&< 2.0.2 | 2.0.2 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for sinatra. 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 sinatra to 2.0.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-mq35-wqvf-r23c 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-mq35-wqvf-r23c 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-mq35-wqvf-r23c. 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-mq35-wqvf-r23c in your dependencies?
O3 detects GHSA-mq35-wqvf-r23c across RubyGems dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.