GHSA-cm8h-q92v-xcfc
MEDIUMmercurius has Uncaught Exception when using subscriptions
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
mercurius📦mercuriusReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects npm packages — download data is not available via public APIs for these ecosystems.
Description
Impact
Any users of Mercurius until version v11.5.0 are subjected to a denial of service attack by sending a malformed packet over WebSocket to /graphql.
Patches
This was patched in https://github.com/mercurius-js/mercurius/pull/940. The patch was released as v11.5.0 and v8.13.2.
Workarounds
Disable subscriptions.
References
Reported publicly as https://github.com/mercurius-js/mercurius/issues/939. The same problem was solved in https://github.com/fastify/fastify-websocket/pull/228
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | mercurius | ≥ 9.0.0&&< 11.5.0 | 11.5.0 |
| 📦npm | mercurius | all versions | 8.13.2 |
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 mercurius. 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 mercurius to 11.5.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-cm8h-q92v-xcfc 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-cm8h-q92v-xcfc 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-cm8h-q92v-xcfc. 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-cm8h-q92v-xcfc in your dependencies?
O3 detects GHSA-cm8h-q92v-xcfc across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.