No exploitation reportedFix available

CVE-2025-66568

Q: Is CVE-2025-66568 actively exploited?

Active exploitation of CVE-2025-66568 has not been confirmed. Its EPSS score was 0.2% on 2026-10-23, the estimated probability of exploitation in the next 30 days.

Q: What is the CVSS score for CVE-2025-66568?

CVE-2025-66568 has a CVSS v3 base score of 9.1 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N.

No exploitation reported by the sources we read.

Published2025-12-09
Fixed in1.18.0
WeaknessCWE-347

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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.

Timeline

dates in UTC

2025-12-0916:18CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2025-66568?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2025-66568?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD · OSV

Onelogin ruby-saml

Branch	Affected	Fixed in	Source
1.18	< 1.18.0	1.18.0	NVD · OSV

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

Update Onelogin ruby-saml to 1.18.0

Advisories and patches

github.comVendor Advisory

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: none listed

Sources

CISA-ADPSSVC decisionnone2025-12-09
OpenCVESSVC decisionnone—
CNACVSS 4.09.3read 2026-10-23
NVDCVSS 3.19.1read 2026-10-23
CNAweakness (CWE)CWE-347read 2026-10-23
FIRST EPSSEPSS score0.2 %2026-10-23
OSVaffected packages—

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
CVSS 4.0 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/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
Published: 2025-12-09
Last Modified: 2026-10-14
NVD status: Analyzed

Frequently asked questions

What is CVE-2025-66568?

Is CVE-2025-66568 actively exploited?

Active exploitation of CVE-2025-66568 has not been confirmed. Its EPSS score was 0.2% on 2026-10-23, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2025-66568?

CVE-2025-66568 has a CVSS v3 base score of 9.1 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N.

Running ruby-saml? Hear about its next vulnerability

Surveillance reads the versions in your stack — a domain, a lockfile or a list — checks each CVE against the ranges its sources publish, and alerts you when one you run is exploited or enters CISA KEV. A version it cannot read stays « version not verified ».

Get alerts for this product CISA KEV additions, October 2026 Search CVEs

No credit card required · No monthly cap on website lookups · 250 API requests/month

Go further

Following what attackers exploit right now? The CISA KEV additions of the month, with their patch deadlines.
Running this software? Vulnerability monitoring alerts you to new vulnerabilities in your products.

Related vulnerabilities

Same product first, then the same vendor advisory and the same publication week.

Back to CVE Database