Vulnerability in Onelogin Ruby-Saml
CVE-2025-66568
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.
EPSS: 0.002 (14.3th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N.
Affected products
- Onelogin Ruby-saml
- Saml-toolkits Ruby-saml — versions < 1.18.0
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Vendor Advisory)
- security-advisories@github.com (x_refsource_MISC, Broken Link)
Frequently asked questions
- What is CVE-2025-66568?
- CVE-2025-66568 is a critical-severity vulnerability in Onelogin Ruby-Saml, classified under Improper Verification of Cryptographic Signature. CVSS score: 9.1/10. Published 2025-12-09.
- How severe is CVE-2025-66568?
- Critical severity. CVSS v3 base score is 9.1 out of 10.