ruby-saml Libxml2 Canonicalization errors can bypass Digest/Signature validation

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

• onelogin ruby-samlbefore 1.18.0

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

• SAML-Toolkits ruby-saml

  • < 1.18.0affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

Other highest-scoring records for the same primary product.

• CVE-2024-45409The Ruby SAML library vulnerable to a SAML authentication bypass via Incorrect XPath selector
  42Plan
• CVE-2017-11428Multiple SAML libraries may allow authentication bypass via incorrect XML canonicalization and DOM traversal
  40Plan
• CVE-2015-20108xml_security.rb in the ruby-saml gem before 1.0.0 for Ruby allows XPath injection and code execution because prepared statements are not use
  39Monitor
• CVE-2025-66567ruby-saml has a SAML authentication bypass due to namespace handling (parser differential)
  37Monitor
• CVE-2016-5697Ruby-saml before 1.3.0 allows attackers to perform XML signature wrapping attacks via unspecified vectors.
  30Monitor

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Root cause

The verifier takes the algorithm to verify with from the token’s own header. Untrusted data ends up deciding its own verification rule.

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

1const claims = jwt.verify(token, publicKey);

1const claims = jwt.verify(token, publicKey, {2  algorithms: ["RS256"],3  issuer: "https://id.example.com",4  audience: "portal",5});

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.