GHSA-jj8c-mmj3-mmgv
MEDIUMGHSA-jj8c-mmj3-mmgv is a medium-severity (CVSS 5.4) Cross-Site Request Forgery (CSRF) vulnerability in authlib. O3 Security confirms whether GHSA-jj8c-mmj3-mmgv is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Authlib: Cross-site request forging when using cache
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
Exploitation and automatability from CISA’s SSVC triage for GHSA-jj8c-mmj3-mmgv.
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.
How urgent is this, really
GHSA-jj8c-mmj3-mmgv plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 0 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
authlibReal-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
There is no CSRF protection on the cache feature on most integrations clients.
Details
In authlib.integrations.starlette_client.OAuth, no CSRF protection is set up when using the cache parameter. When not using the cache parameter, the use of SessionMiddleware ties the client to the auth state, preventing CSRF attacks. With the cache, there is no such mechanism. Other integratons have the same issue, it's not just starlette.
The state parameter is taken from the callback URL and the state is fetched from the cache without checking that it is the same client calling the redirect endpoint as was the one that initiated the auth flow.
This issue is documented in RFC 6749 section 10.12: https://datatracker.ietf.org/doc/html/rfc6749#section-10.12
PoC
- Set up a Starlette integration with a cache
- The attacker starts the auth flow up until before the callback URL is followed.
- The attacked sends the redirect URL to the victim
- The victim now completes the authorisation
Impact
This impacts all users that use the cache to store auth state.
All users will be vulnerable to CSRF attacks and may have an attacker's account tied to their own.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | authlib | all versions | 1.6.11 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for authlib. 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 authlib to 1.6.11 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-jj8c-mmj3-mmgv 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-jj8c-mmj3-mmgv 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-jj8c-mmj3-mmgv. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
Frequently Asked Questions
Is GHSA-jj8c-mmj3-mmgv in your dependencies?
O3 detects GHSA-jj8c-mmj3-mmgv across PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.