🛡️ CVE-2025-66567 — ruby-saml

🔴 CVSS 9.5 — Critical ✅ No Known Exploit CWE-347 OSV
9.5
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

Ruby-saml has a SAML authentication bypass due to namespace handling (parser differential) ### 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

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. Rated impact: confidentiality high, integrity high, availability none.

Weakness class

CVE-2025-66567 is classified as CWE-347: Improper Verification of Cryptographic Signature. A signature is not checked correctly, so forged or modified content is accepted as genuine.

Affected software and timeline

Affected software: ruby-saml (fixed in 1.18.0). Published on 8 December 2025 and last revised on 17 June 2026. No public exploit is currently recorded for this entry. A vendor advisory or fix has been published. Record sourced from OSV.

References

github.com (Web)
nvd.nist.gov (Advisory)
github.com (Web)
github.com (Package)
github.com (Advisory)
github.com (Web)

CVE-2025-66567 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Details

Severity CRITICAL
CVSS Score 9.5
CVSS Vector 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
CWE CWE-347
Public Exploit ✅ No
Source OSV
Published 2025-12-08
Updated 2026-08-12
Modified 2026-06-17

Affected Packages

Software From version Fixed in
ruby-saml — 1.18.0

Similar Threats

Exploit Protection

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More CVE 2025 advisories

Part of CVE 2025 in the advisory index.