CVE-2025-29774: xml-crypto Vulnerable to XML Signature Verification Bypass via Multiple SignedInfo References

Should you act?

High exploit likelihood

EPSS ranks it in the top 5% of all CVEs for likely exploitation in the next 30 days. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• Not in CISA KEV, but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
• EPSS 9.1%, percentile 95: FIRST’s model estimates a 9.1% chance of exploitation activity in the next 30 days, higher than 95% of all scored CVEs (very high). EPSS is a probability, not a verdict.
• Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
• Only applies if your dependency tree includes xml-crypto (npm) >= 4.0.0, < 6.0.1, fixed in 6.0.1; xml-crypto (npm) >= 3.0.0, < 3.2.1, fixed in 3.2.1; xml-crypto (npm) < 2.1.6, fixed in 2.1.6. Check your lockfile, including transitive dependencies.

What it is

xml-crypto is an XML digital signature and encryption library for Node.js. An attacker may be able to exploit a vulnerability in versions prior to 6.0.1, 3.2.1, and 2.1.6 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. Users of versions 6.0.0 and prior should upgrade to version 6.0.1 to receive a fix. Those who are still using v2.x or v3.x should upgrade to patched versions 2.1.6 or 3.2.1, respectively.

From the GitHub advisory

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

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.

Weakness type: CWE-347.

Product: xml-crypto (npm) · Assigned by: GitHub_M · Published: 2025-03-14

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: low
• Attack requirements: none
• Privileges required: none (no login)
• User interaction: none

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
• CISA SSVC assessment: exploitation poc, automatable yes, technical impact total.
• FIRST EPSS (model of 2026-10-21): 9.10% probability of exploitation activity in the next 30 days; percentile 95.

Timeline

• 2025-03-14 — CVE record published by GitHub_M
• 2025-03-14 — GitHub-reviewed advisory GHSA-9p8x-f768-wp2g published (critical)
• 2025-03-15 — CVE record last updated

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vulnerability records

1. GitHub Advisory GHSA-9p8x-f768-wp2g github.com
2. CVE.org record CVE-2025-29774 cve.org
3. NVD entry CVE-2025-29774 nvd.nist.gov

Other references from the CVE record and advisory

1. github.com github.com
2. github.com github.com
3. github.com github.com
4. github.com github.com
5. github.com github.com
6. github.com github.com
7. github.com github.com
8. workos.com workos.com

Critical npm advisories · Today’s Security Digest