GHSA-5p3x-r448-pc62
MEDIUMGHSA-5p3x-r448-pc62 is a medium-severity (CVSS 6.5) CWE-347 vulnerability in pysaml2. 1 public exploit reference exists, so weaponization risk is real. O3 Security confirms whether GHSA-5p3x-r448-pc62 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Improper Verification of Cryptographic Signature in PySAML2
Blast Radius
pysaml2Real-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
Impact
All users of pysaml2 that use the default CryptoBackendXmlSec1 backend and need to verify signed SAML documents are impacted. pysaml2 <= 6.4.1 does not ensure that a signed SAML document is correctly signed. The default CryptoBackendXmlSec1 backend is using the xmlsec1 binary to verify the signature of signed SAML documents, but by default, xmlsec1 accepts any type of key found within the given document. xmlsec1 needs to be configured explicitly to only use only x509 certificates for the verification process of the SAML document signature.
Patches
Users should upgrade to pysaml2 v6.5.0.
Workarounds
No workaround provided at this point.
References
This issue has been reported in the past at the xmlsec1 mailing list: https://www.aleksey.com/pipermail/xmlsec/2013/009717.html
Credits
- Brian Wolff
For more information
If you have any questions or comments about this advisory:
- Open an issue in pysaml2
- Email us at the incident-response address
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | pysaml2 | all versions | 6.5.0 |
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 pysaml2. 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 pysaml2 to 6.5.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-5p3x-r448-pc62 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-5p3x-r448-pc62 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-5p3x-r448-pc62. 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-5p3x-r448-pc62 in your dependencies?
O3 detects GHSA-5p3x-r448-pc62 across PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.