CVE-2025-25291: ruby-saml · Improper Verification of Cryptographic Signature
Affects ruby-samlSource CVE Database V5
Not known to be exploited · 20% EPSS · CVSS 9.3 Critical : upgrade to 1.12.4 as a priority.
Data as of 25 Oct 2026, 19:02 UTC
- EPSS
- 20.9% chance of exploitation in 30 days – higher than 97% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 1.12.4
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 12 Mar 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-25.
What to do
Upgrade ruby-saml to 1.12.4.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| SAML-Toolkits ruby-saml | Affected
| Fixed in
|
AI-suggested
European organizations should immediately upgrade ruby-saml to versions 1.12.4 or 1.18.0 where the vulnerability is patched. Beyond upgrading, organizations should audit their SAML implementations to ensure consistent XML parsing and signature verification processes. Employing XML security libraries that are resistant to signature wrapping attacks or implementing additional validation layers can reduce risk. Monitoring authentication logs for anomalies indicative of signature wrapping or unusual SSO activity is recommended. Organizations should also conduct penetration testing focused on SAML assertion handling to detect potential exploitation paths. Where feasible, consider implementing multi-factor authentication (MFA) to mitigate the impact of authentication bypass. Finally, maintain up-to-date threat intelligence and apply security patches promptly to reduce exposure windows.
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.
References
- github.com/SAML-Toolkits/ruby-saml/security/advisories/GHSA-4vc4-m8qh-g8jm (opens in a new tab)
- github.com/omniauth/omniauth-saml/security/advisories/GHSA-hw46-3hmr-x9xv (opens in a new tab)
- github.com/SAML-Toolkits/ruby-saml/commit/e76c5b36bac40aedbf1ba7ffaaf495be63328cd9 (opens in a new tab)
- github.com/SAML-Toolkits/ruby-saml/commit/e9c1cdbd0f9afa467b585de279db0cbd0fb8ae97 (opens in a new tab)
- about.gitlab.com/releases/2025/03/12/patch-release-gitlab-17-9-2-released (opens in a new tab)
- github.blog/security/sign-in-as-anyone-bypassing-saml-sso-authentication-with-parser-differentials (opens in a new tab)
- github.com/SAML-Toolkits/ruby-saml/releases/tag/v1.12.4 (opens in a new tab)
- github.com/SAML-Toolkits/ruby-saml/releases/tag/v1.18.0 (opens in a new tab)
- portswigger.net/research/saml-roulette-the-hacker-always-wins (opens in a new tab)
- securitylab.github.com/advisories/GHSL-2024-329_GHSL-2024-330_ruby-saml (opens in a new tab)
- security.netapp.com/advisory/ntap-20250314-0010/ (opens in a new tab)
- news.ycombinator.com/item?id=43374519 (opens in a new tab)
- lists.debian.org/debian-lts-announce/2025/04/msg00011.html (opens in a new tab)