Vulnerability in Node-SAML SAML Library Allows Modification of Assertions

CVE-2025-54419

What is CVE-2025-54419?

A vulnerability in the Node-SAML SAML library allows unauthorized modification of authentication details in valid SAML assertions. Specifically, in version 5.0.1, the library loads assertions from the original unsigned response document, which does not undergo full verification against signatures. This oversight enables attackers to alter critical elements, including usernames, of a valid SAML assertion, provided they possess a legitimately signed document from the identity provider (IdP). This issue has been addressed in version 5.1.0.

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