CVE-2025-54369: Node-SAML SAML Authentication Bypass

Should you act?

Critical and remotely reachable

No known exploitation yet, but it is network-reachable without credentials. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
• EPSS 0.5%, percentile 45: FIRST’s model estimates a 0.5% chance of exploitation activity in the next 30 days, higher than 45% of all scored CVEs (low). 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 node-saml (npm) <= 3.1.2, no fixed version listed; @node-saml/node-saml (npm) <= 5.0.1, fixed in 5.1.0. Check your lockfile, including transitive dependencies.

What it is

Node-SAML is a SAML library not dependent on any frameworks that runs in Node. In versions 5.0.1 and below, 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. This issue is fixed in version 5.1.0.

From the GitHub advisory

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 upgraded xml-crypto to v6.1.2 and made sure to process the SAML assertions from only verified/authenticated contents. This will prevent future variants from coming up.

Weakness type: CWE-87, CWE-347, CWE-287.

Product: node-saml (npm) · Assigned by: GitHub_M · Published: 2025-12-12

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 none, automatable yes, technical impact partial.
• FIRST EPSS (model of 2026-10-21): 0.55% probability of exploitation activity in the next 30 days; percentile 45.

Timeline

• 2025-07-25 — GitHub-reviewed advisory GHSA-m837-g268-mmv7 published (critical)
• 2025-12-12 — CVE record published by GitHub_M
• 2026-05-07 — 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-m837-g268-mmv7 github.com
2. CVE.org record CVE-2025-54369 cve.org
3. NVD entry CVE-2025-54369 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

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