No exploitation reportedFix available

CVE-2025-66567

Q: Is CVE-2025-66567 actively exploited?

Active exploitation of CVE-2025-66567 has not been confirmed. Its EPSS score was 0.4% on 2026-10-23, the estimated probability of exploitation in the next 30 days.

Q: What is the CVSS score for CVE-2025-66567?

CVE-2025-66567 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 is for implementing the client side of a SAML authorization. ruby-saml versions up to and including 1.12.4 contain an authentication bypass vulnerability due to an incomplete fix for CVE-2025-25292. ReXML and Nokogiri parse XML differently, generating entirely different document structures from the same input. This allows an attacker to execute a Signature Wrapping attack. 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-2025-66567?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2025-66567?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.comPatch
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 score0.4 %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-2025-66567?

Is CVE-2025-66567 actively exploited?

Active exploitation of CVE-2025-66567 has not been confirmed. Its EPSS score was 0.4% on 2026-10-23, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2025-66567?

CVE-2025-66567 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.

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