GHSA-5cmr-4px5-23pc is a high-severity (CVSS 7.5) CWE-674 vulnerability in xgrammar. O3 Security confirms whether GHSA-5cmr-4px5-23pc is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
XGrammar affected by Denial of Service by infinite recursion grammars
Real-World Exposure
xgrammarReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
Summary
This issue: http://github.com/mlc-ai/xgrammar/issues/250 should have it's own security advisory. Since several tools accept and pass user supplied grammars to xgrammar, and it is so easy to trigger it seems like a High.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | xgrammar | all versions | 0.1.21 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for xgrammar. 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 xgrammar to 0.1.21 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-5cmr-4px5-23pc 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-5cmr-4px5-23pc 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-5cmr-4px5-23pc. 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-5cmr-4px5-23pc in your dependencies?
O3 detects GHSA-5cmr-4px5-23pc across PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.