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CVE-2025-66568

ruby-saml Libxml2 Canonicalization errors can bypass Digest/Signature validation

Published: Dec 9, 2025Updated: Dec 10, 2025 Sources: CVE List NVD GHSACWE-347
NVD MITRE
9.1CVSSCRITICAL
EPSS Score
0.2%
Top 89.3%
CISA KEV
Not in KEV
Exploits
1 Known
Remediation
Patch Available

Description

The ruby-saml library implements the client side of an SAML authorization. Versions up to and including 1.12.4, are vulnerable to authentication bypass through the libxml2 canonicalization process used by Nokogiri for document transformation, which allows an attacker to execute a Signature Wrapping attack. When libxml2’s canonicalization is invoked on an invalid XML input, it may return an empty string rather than a canonicalized node. ruby-saml then proceeds to compute the DigestValue over this empty string, treating it as if canonicalization succeeded. This issue is fixed in version 1.18.0.

CVSS Vector Breakdown

AV:NAC:LPR:NUI:NS:UC:HI:HA:N
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:HConfidentiality
High
I:HIntegrity
High
A:NAvailability
None
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Weaknesses

CWE-347

Affected Products

ruby-samlonelogin
SaaS
Security Products / identity-access-mgmt
ruby-samlSAML-Toolkits
Library
OSS Libraries / generic-library
ruby-samlRubyGemsOSS Libraries
onelogincommercialUSSecurity Productsaka onelogin saml sso, onelogin saml
saml-toolkitsoss-projectOSS Librariesaka ruby-saml, saml-toolkits ruby-saml
rubygemspackage-ecosystemOSS Libraries

Attack Graph

Products CVE Techniques Tactics

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Exploitability

1 exploit source identified

Exploit details including PoC links, Metasploit modules, and scanner templates are available after registration.

View exploit details
Official Patch Available

MITRE ATT&CK

1 technique
Collection
View detailed technique mapping

References

https://github.com/SAML-Toolkits/ruby-saml/commit/acac9e9cc0b9a507882c614f25d41f8b47be349a
github.com
https://github.com/SAML-Toolkits/ruby-saml/security/advisories/GHSA-x4h9-gwv3-r4m4
github.com
https://nvd.nist.gov/vuln/detail/CVE-2025-66568
nvd.nist.gov
and 2 more references View all →

Timeline

Published
Dec 9, 2025
Last Updated
Dec 10, 2025

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