GHSA-pxm4-r5ph-q2m2 is a high-severity (CVSS 8.3) XML External Entity (XXE) vulnerability in simplesamlphp/saml2. O3 Security confirms whether GHSA-pxm4-r5ph-q2m2 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
SimpleSAMLphp SAML2 has an XXE in parsing SAML messages
Real-World Exposure
simplesamlphp/saml2🐘simplesamlphp/saml2-legacyReal-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
Summary
When loading an (untrusted) XML document, for example the SAMLResponse, it's possible to induce an XXE.
$options is defined as: https://github.com/simplesamlphp/saml2/blob/717c0adc4877ebd58428637e5626345e59fa0109/src/SAML2/DOMDocumentFactory.php#L41 including the DTDLoad option, which allows an attacker to read file contents from local file system OR internal network.
While there is the NONET option, an attacker can simply bypass if by using PHP filters: php://filter/convert.base64-encode/resource=http://URL OR FILE
From there an attacker can induce network connections and steal the targeted file OOB (haven't fully tested this).
RCE may be possible with the php://expect or php://phar wrappers, but this hasn't been tested.
Note: The mitigation here: https://github.com/simplesamlphp/saml2/blob/717c0adc4877ebd58428637e5626345e59fa0109/src/SAML2/DOMDocumentFactory.php#L63-L69 Comes too late, as the XML has already been loaded into a document. Mitigation:
Remove the LIBXML_DTDLOAD | LIBXML_DTDATTR options. Additionally, as a defense in depth measure, check if there is the string: <!DOCTYPE inside the XML before parsing it. (This is not a complete fix because someone may be able to exploit some parser differentials, to load a DOCTYPE, maybe through spacing like: <! DOCTYPE)
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | simplesamlphp/saml2 | all versions | 4.6.14 |
| 🐘Packagist | simplesamlphp/saml2-legacy | all versions | 4.6.14 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for simplesamlphp/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 simplesamlphp/saml2 to 4.6.14 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-pxm4-r5ph-q2m2 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-pxm4-r5ph-q2m2 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-pxm4-r5ph-q2m2. 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-pxm4-r5ph-q2m2 in your dependencies?
O3 detects GHSA-pxm4-r5ph-q2m2 across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.