GHSA-4vc4-m8qh-g8jm
CRITICALGHSA-4vc4-m8qh-g8jm is a critical-severity (CVSS 9.8) CWE-347 vulnerability in ruby-saml. O3 Security confirms whether GHSA-4vc4-m8qh-g8jm is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Ruby SAML allows a SAML authentication bypass due to DOCTYPE handling (parser differential)
Blast Radius
ruby-saml💎ruby-samlReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects RubyGems packages — download data is not available via public APIs for these ecosystems.
Description
Summary
An authentication bypass vulnerability was found in ruby-saml due to a parser differential. ReXML and Nokogiri parse XML differently, the parsers can generate entirely different document structures from the same XML input. That allows an attacker to be able to execute a Signature Wrapping attack.
Impact
This issue may lead to authentication bypass.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💎RubyGems | ruby-saml | all versions | 1.12.4 |
| 💎RubyGems | ruby-saml | ≥ 1.13.0&&< 1.18.0 | 1.18.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for ruby-saml. 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 ruby-saml to 1.12.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-4vc4-m8qh-g8jm 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-4vc4-m8qh-g8jm 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-4vc4-m8qh-g8jm. 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-4vc4-m8qh-g8jm in your dependencies?
O3 detects GHSA-4vc4-m8qh-g8jm across RubyGems dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.