The ruby-saml library implements the client side of an SAML authorization. Versions up to and including 1.12.4, are vulnerable to authentication bypass through the libxml2 canonicalization process used by Nokogiri for document transformation, which allows an attacker to execute a Signature Wrapping attack. When libxml2’s canonicalization is invoked on an invalid XML input, it may return an empty string rather than a canonicalized node. ruby-saml then proceeds to compute the DigestValue over this empty string, treating it as if canonicalization succeeded. This issue is fixed in version 1.18.0.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - The ruby-saml library implements the client side of an SAML authorization. Versions up to and including     1.12.4, are vulnerable to authentication bypass through the libxml2 canonicalization process used by     Nokogiri for document transformation, which allows an attacker to execute a Signature Wrapping attack.
    When libxml2's canonicalization is invoked on an invalid XML input, it may return an empty string rather     than a canonicalized node. ruby-saml then proceeds to compute the DigestValue over this empty string,     treating it as if canonicalization succeeded. This issue is fixed in version 1.18.0. (CVE-2025-66568)

Note that Nessus relies on the presence of the package as reported by the vendor.

There are packages installed that are affected by a vulnerability referenced in the following CVE:

  - The ruby-saml library implements the client side of an SAML authorization. Versions up to and including
    1.12.4, are vulnerable to authentication bypass through the libxml2 canonicalization process used by
    Nokogiri for document transformation, which allows an attacker to execute a Signature Wrapping attack.
    When libxml2’s canonicalization is invoked on an invalid XML input, it may return an empty string rather
    than a canonicalized node. ruby-saml then proceeds to compute the DigestValue over this empty string,
    treating it as if canonicalization succeeded. This issue is fixed in version 1.18.0. (CVE-2025-66568)

ID	Name	Product	Family	Type	Severity
278384	Linux Distros Unpatched Vulnerability : CVE-2025-66568	Nessus	Misc.	Local	critical
436298	SCA: security update for ruby-saml (GHSA-x4h9-gwv3-r4m4)	Tenable Cloud Security	SCA Checks	Local	critical
436298	SCA: security update for ruby-saml (GHSA-x4h9-gwv3-r4m4)	Tenable Self-Hosted Container Security	SCA Checks	Local	critical

Detections

Analytics

CVE-2025-66568

critical

Tenable Plugins

critical

critical

critical