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CVE-2025-66568

31
FAUCET Score

CVE-2025-66568 is a critical authentication bypass vulnerability in the ruby-saml library (versions up to 1.12.4), affecting products like onelogin ruby_saml. This flaw, rated 9.1 CRITICAL, allows attackers to execute a Signature Wrapping attack due to improper handling of libxml2 canonicalization, leading to high impact on confidentiality and integrity without requiring user interaction. While there is no known active exploitation or public exploit code (Metasploit, Nuclei, ExploitDB), the vulnerability has garnered significant community discussion and media coverage, indicating awareness and potential future exploitation. Organizations using affected versions should upgrade to 1.18.0 or later immediately.

Impacted Technologies

VendorProductVersion(s)CPE
< 1.18.0CPE matchmatch criteria
cpe:2.3:a:onelogin:ruby-saml:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 4.0

9.3CRITICAL

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
NONE
VS Confidentiality
HIGH
VS Integrity
HIGH
VS Availability
NONE
SS Confidentiality
NONE
SS Integrity
NONE
SS Availability
NONE
Exploit Maturity
NOT_DEFINED
CvssVersion
4.0

Exploit Intelligence

EPSS Score
0.21%
Probability of exploitation in next 30 days
EPSS Percentile
11.5%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0021 is in the 0th percentile among its peer group of 36,862 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.3 Bluesky, 0.3 Mastodon, and 2.4 GitHub mentions.

Media Mentions

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (2)

rubygemspatch availablevia ghsa
Product: ruby-samlFixed in: 1.18.0
github_advisoryvendor investigatingvia nvd_reference
View patch

Vendor Advisories (1)

rubygemsGHSA-x4h9-gwv3-r4m4critical

Ruby-saml allows a Libxml2 Canonicalization error to bypass Digest/Signature validation

Dec 8, 2025

References

github.com / SAML-Toolkits/ruby-saml/commit/acac9e9cc0b9a507882c614f25d41f8b47be349a
Broken Link
github.com / SAML-Toolkits/ruby-saml/security/advisories/GHSA-x4h9-gwv3-r4m4
Vendor Advisory