GHSA-9p8x-f768-wp2g
xml-crypto Vulnerable to XML Signature Verification Bypass via Multiple SignedInfo References
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
Weekly download volume for affected packages — a proxy for how broadly this vulnerability is deployed.
xml-cryptonpmDescription
Impact
An attacker may be able to exploit this vulnerability to bypass authentication or authorization mechanisms in systems that rely on xml-crypto for verifying signed XML documents. The vulnerability allows an attacker to modify a valid signed XML message in a way that still passes signature verification checks. For example, it could be used to alter critical identity or access control attributes, enabling an attacker with a valid account to escalate privileges or impersonate another user.
Patches
All versions <= 6.0.0 are affected. Please upgrade to version 6.0.1.
If you are still using v2.x or v3.x please upgrade to the associated patch version.
Indicators of Compromise
When logging XML payloads, check for the following indicators. If the payload includes encrypted elements, ensure you analyze the decrypted version for a complete assessment. (If encryption is not used, analyze the original XML document directly). This applies to various XML-based authentication and authorization flows, such as SAML Response payloads.
Multiple SignedInfo Nodes
There should not be more than one SignedInfo node inside a Signature. If you find multiple SignedInfo nodes, it could indicate an attack.
<Signature>
<SomeNode>
<SignedInfo>
<Reference URI="somefakereference">
<DigestValue>forgeddigestvalue</DigestValue>
</Reference>
</SignedInfo>
</SomeNode>
<SignedInfo>
<Reference URI="realsignedreference">
<DigestValue>realdigestvalue</DigestValue>
</Reference>
</SignedInfo>
</SignedInfo>
</Signature>
Code to test
Pass in the decrypted version of the document
decryptedDocument = ... // yours to implement
// This check is per-Signature node, not per-document
const signedInfoNodes = xpath.select(".//*[local-name(.)='SignedInfo']", signatureNode);
if (signedInfoNodes.length === 0) {
// Not necessarily a compromise, but invalid. Should contain exactly one SignedInfo node
// Yours to implement
}
if (signedInfoNodes.length > 1) {
// Compromise detected, yours to implement
}
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | xml-crypto | ≥ 4.0.0&&< 6.0.1 | 6.0.1 |
| 📦npm | xml-crypto | ≥ 3.0.0&&< 3.2.1 | 3.2.1 |
| 📦npm | xml-crypto | all versions | 2.1.6 |
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 xml-crypto. 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 xml-crypto to 6.0.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-9p8x-f768-wp2g 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-9p8x-f768-wp2g 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-9p8x-f768-wp2g. 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-9p8x-f768-wp2g in your dependencies?
O3 detects GHSA-9p8x-f768-wp2g across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.