ruby-saml provides security assertion markup language (SAML) single sign-on (SSO) for Ruby. An authentication bypass vulnerability was found in ruby-saml prior to versions 1.12.4 and 1.18.0 due to a parser differential. ReXML and Nokogiri parse XML differently, the parsers can generate entirely different document structures from the same XML input. That allows an attacker to be able to execute a Signature Wrapping attack. This issue may lead to authentication bypass. Versions 1.12.4 and 1.18.0 contain a patch for the issue.

AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CWE-347

CWE-436

https://about.gitlab.com/releases/2025/03/12/patch-release-gitlab-17-9-2-released

https://github.com/SAML-Toolkits/ruby-saml/commit/e76c5b36bac40aedbf1ba7ffaaf495be63328cd9

https://github.com/SAML-Toolkits/ruby-saml/commit/e9c1cdbd0f9afa467b585de279db0cbd0fb8ae97

https://github.com/SAML-Toolkits/ruby-saml/releases/tag/v1.12.4

https://github.com/SAML-Toolkits/ruby-saml/releases/tag/v1.18.0

https://github.com/SAML-Toolkits/ruby-saml/security/advisories/GHSA-754f-8gm6-c4r2

https://github.com/omniauth/omniauth-saml/security/advisories/GHSA-hw46-3hmr-x9xv