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Vulnerability record · CVE-2025-25291 · published 12 March 2025

CVE-2025-25291: Omniauth saml improper verification of cryptographic signature vulnerability

Omniauth · Omniauth Saml

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 fix the issue.

9.3 CVSS 4.0 Critical EPSS 21% · top 2.6% CWE-347 · Improper verification of cryptographic signatureCWE-436 · Interpretation conflict
9.3CVSS 4.0 base score
21%EPSS exploitation probability, 30 days
NoNot in CISA KEV
3Affected product versions listed by NVD
13References, 2 tagged exploit
17 Jun 2026Last modified by NVD

Description

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 fix the issue.

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/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:

Affected products

3 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://about.gitlab.com/releases/2025/03/12/patch-release-gitlab-17-9-2-released Patch
https://github.blog/security/sign-in-as-anyone-bypassing-saml-sso-authentication-with-parser-differentials ExploitThird Party Advisory
https://github.com/SAML-Toolkits/ruby-saml/commit/e76c5b36bac40aedbf1ba7ffaaf495be63328cd9 Patch
https://github.com/SAML-Toolkits/ruby-saml/commit/e9c1cdbd0f9afa467b585de279db0cbd0fb8ae97 Patch
https://github.com/SAML-Toolkits/ruby-saml/releases/tag/v1.12.4 Release Notes
https://github.com/SAML-Toolkits/ruby-saml/releases/tag/v1.18.0 Release Notes
https://github.com/SAML-Toolkits/ruby-saml/security/advisories/GHSA-4vc4-m8qh-g8jm Vendor Advisory
https://github.com/omniauth/omniauth-saml/security/advisories/GHSA-hw46-3hmr-x9xv Vendor Advisory
https://portswigger.net/research/saml-roulette-the-hacker-always-wins ExploitThird Party Advisory
https://securitylab.github.com/advisories/GHSL-2024-329_GHSL-2024-330_ruby-saml Third Party Advisory
https://lists.debian.org/debian-lts-announce/2025/04/msg00011.html
https://news.ycombinator.com/item?id=43374519 Issue Tracking
https://security.netapp.com/advisory/ntap-20250314-0010/ Third Party Advisory

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Source: NIST National Vulnerability Database (record CVE-2025-25291), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.