GHSA-4mxg-3p6v-xgq3 is a critical-severity (CVSS 10) Improper Authentication vulnerability in @node-saml/node-saml. A fix is available for @node-saml/node-saml — see the affected versions and patch details below.
Node-SAML SAML Signature Verification Vulnerability
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-4mxg-3p6v-xgq3.
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.
How urgent is this, really
GHSA-4mxg-3p6v-xgq3 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 378,567 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
@node-saml/node-samlnpmpassport-samlnpm@node-saml/passport-samlnpmDescription
Node-SAML loads the assertion from the (unsigned) original response document. This is different than the parts that are verified when checking signature.
This allows an attacker to modify authentication details within a valid SAML assertion. For example, in one attack it is possible to remove any character from the SAML assertion username.
To conduct the attack an attacker would need a validly signed document from the identity provider (IdP).
In fixing this we made sure to process the SAML assertions from only verified/authenticated contents. This will prevent future variants from coming up.
Note: this is distinct from the previous xml-crypto CVEs.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | @node-saml/node-saml | all versions | 5.1.0npm install @node-saml/node-saml@5.1.0 |
| 📦npm | passport-saml | all versions | No fix |
| 📦npm | @node-saml/passport-saml | all versions | 5.1.0npm install @node-saml/passport-saml@5.1.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @node-saml/node-saml, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update @node-saml/node-saml to 5.1.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-4mxg-3p6v-xgq3 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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-4mxg-3p6v-xgq3 can be triaged on real exposure rather than presence alone.
Tailored to GHSA-4mxg-3p6v-xgq3. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
This is a Important impact authn-bypass, not a Moderate bug, because it breaks the core trust boundary of SAML: the service provider (SP) makes authorization decisions based on an assertion it believes is protected by the IdP’s XML signature. In @node-saml/node-saml ≤5.0.1, the library verifies the signature over one…
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat Developer Hub 1.7 | rhdh/rhdh-hub-rhel9:1.7.0-1754936470 | RHSA-2025:14090 |
Frequently Asked Questions
Is GHSA-4mxg-3p6v-xgq3 in your dependencies?
O3 Security finds GHSA-4mxg-3p6v-xgq3 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.