GHSA-g6j2-ch25-5mmv is a high-severity (CVSS 8.2) CWE-294 vulnerability in Sustainsys.Saml2. O3 Security confirms whether GHSA-g6j2-ch25-5mmv is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Missing Token Replay Detection in Saml2 Authentication services for ASP.NET
Real-World Exposure
Sustainsys.Saml2Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects NuGet packages — download data is not available via public APIs for these ecosystems.
Description
Impact
Token Replay Detection is an important defence in depth measure for Single Sign On solutions. In all previous 2.X versions, the Token Replay Detection is not properly implemented.
Note that version 1.0.1 is not affected. It has a correct Token Replay Implementation and is safe to use.
Patches
The 2.5.0 version is patched.
Workarounds
There are no workarounds with existing versions. Fixing the issue requires code updates.
References
https://en.wikipedia.org/wiki/Replay_attack
For more information
If you have any questions or comments about this advisory:
- Comment on #711.
- Email us at [email protected] if you think that there are further security issues.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| .NETNuGet | Sustainsys.Saml2 | ≥ 2.0.0&&< 2.5.0 | 2.5.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for Sustainsys.Saml2. 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 Sustainsys.Saml2 to 2.5.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-g6j2-ch25-5mmv 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-g6j2-ch25-5mmv 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-g6j2-ch25-5mmv. 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-g6j2-ch25-5mmv in your dependencies?
O3 detects GHSA-g6j2-ch25-5mmv across NuGet dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.