GHSA-g8x5-p9qc-cf95
HIGH@fastify/oauth2 vulnerable to Cross Site Request Forgery due to reused Oauth2 state
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
@fastify/oauth2Real-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
All versions of @fastify/oauth2 used a statically generated state parameter at startup time and were used across all requests for all users.
The purpose of the Oauth2 state parameter is to prevent Cross-Site-Request-Forgery attacks. As such, it should be unique per user and should be connected to the user's session in some way that will allow the server to validate it.
Patches
v7.2.0 changes the default behavior to store the state in a cookie with the http-only and same-site=lax attributes set. The state is now by default generated for every user.
Note that this contains a breaking change in the checkStateFunction function, which now accepts the full Request object.
Workarounds
There are no known workarounds.
References
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | @fastify/oauth2 | all versions | 7.2.0 |
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 @fastify/oauth2. 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 @fastify/oauth2 to 7.2.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-g8x5-p9qc-cf95 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-g8x5-p9qc-cf95 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-g8x5-p9qc-cf95. 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-g8x5-p9qc-cf95 in your dependencies?
O3 detects GHSA-g8x5-p9qc-cf95 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.