Open-source package vulnerability · RubyGems

CVE-2025-66567: Ruby-saml has a SAML authentication bypass due to namespace handling (parser differential)

criticalCVSS 4.0 9.3GHSA-9v8j-x534-2fx3

Summary Ruby-saml up to and including 1.12.4, there is an authentication bypass vulnerability because of an incomplete fix for CVE-2025-25292. 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. The vulnerability does not affect the version 1.18.0.

Published Dec 8, 2025 · Updated Dec 12, 2025

Affected packages

ruby-saml

Ecosystem: RubyGems
Affected: < 1.18.0
Fixed in: 1.18.0
Check: bundle info ruby-saml

Advisory details

From the GitHub Advisory Database (CC BY 4.0).

Summary

Ruby-saml up to and including 1.12.4, there is an authentication bypass vulnerability because of an incomplete fix for CVE-2025-25292. 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. The vulnerability does not affect the version 1.18.0.

Impact

That allows an attacker to be able to execute a Signature Wrapping attack and bypass the authentication

Credited to d0ge.

References

How this page is made: the data panel comes from the GitHub Advisory Database, CISA’s KEV catalog, the NVD and FIRST EPSS, and updates twice a day. No analysis has been written for this entry yet. Methodology

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