CVE-2025-25291

ruby-saml vulnerable to SAML authentication bypass due to DOCTYPE handling (parser differential)

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.

Category

9.3
CVSS
Severity: Critical
CVSS 4.0 •
EPSS 1.87% Top 20%
Affected: SAML-Toolkits ruby-saml
Published at:
Updated at:

References

Link Tags
https://github.com/SAML-Toolkits/ruby-saml/security/advisories/GHSA-4vc4-m8qh-g8jm
https://github.com/omniauth/omniauth-saml/security/advisories/GHSA-hw46-3hmr-x9xv
https://github.com/SAML-Toolkits/ruby-saml/commit/e76c5b36bac40aedbf1ba7ffaaf495be63328cd9
https://github.com/SAML-Toolkits/ruby-saml/commit/e9c1cdbd0f9afa467b585de279db0cbd0fb8ae97
https://about.gitlab.com/releases/2025/03/12/patch-release-gitlab-17-9-2-released
https://github.blog/security/sign-in-as-anyone-bypassing-saml-sso-authentication-with-parser-differentials
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://portswigger.net/research/saml-roulette-the-hacker-always-wins
https://news.ycombinator.com/item?id=43374519
https://security.netapp.com/advisory/ntap-20250314-0010/

Frequently Asked Questions

What is the severity of CVE-2025-25291?
CVE-2025-25291 has been scored as a critical severity vulnerability.
How to fix CVE-2025-25291?
To fix CVE-2025-25291, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2025-25291 being actively exploited in the wild?
It is possible that CVE-2025-25291 is being exploited or will be exploited in a near future based on public information. According to its EPSS score, there is a ~2% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2025-25291?
CVE-2025-25291 affects SAML-Toolkits ruby-saml.
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