CVE-2025-66568 — ruby-saml Libxml2 Canonicalization errors can bypass Digest/Signature validation
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 canon…
Published: 2025-12-09 · CVSS: 9.3 · CVSS 4.0
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.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7