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
simplesamlphp/xml-security🐘simplesamlphp/saml2Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.
Description
Validation of an XML Signature requires verification that the hash value of the related XML-document (after any optional transformations and/or normalizations) matches a specific DigestValue-value, but also that the cryptografic signature on the SignedInfo-tree (the one that contains the DigestValue) verifies and matches a trusted public key.
Within the simpleSAMLphp/xml-security library (https://github.com/simplesamlphp/xml-security), the hash is being validated using SignedElementTrait::validateReference, and the signature is being verified in SignedElementTrait::verifyInternal
https://github.com/simplesamlphp/xml-security/blob/master/src/XML/SignedElementTrait.php:
What stands out is that the signature is being calculated over the canonical version of the SignedInfo-tree. The validateReference method, however, uses the original non-canonicalized version of SignedInfo.
Impact
If an attacker somehow (i.e. by exploiting a bug in PHP's canonicalization function) manages to manipulate the canonicalized version's DigestValue, it would be potentially be possible to forge the signature. No possibilities to exploit this were found during the investigation.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | simplesamlphp/xml-security | ≥ 1.6.11&&< 1.6.12 | 1.6.12 |
| 🐘Packagist | simplesamlphp/saml2 | ≥ 5.0.0-alpha.12&&< 5.0.0-alpha.13 | 5.0.0-alpha.13 |
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 simplesamlphp/xml-security. 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 simplesamlphp/xml-security to 1.6.12 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-ww7x-3gxh-qm6r 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-ww7x-3gxh-qm6r 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-ww7x-3gxh-qm6r. 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-ww7x-3gxh-qm6r in your dependencies?
O3 detects GHSA-ww7x-3gxh-qm6r across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.