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Fencer Vulns
medium 5.0

CVE-2025-66406 json

Improper Authorization Check for SSH Certificate Revocation

published 2025-12-03 11 mo ago modified 2026-10-18 21 d ago also EUVD-2025-201014 , GHSA-j7c9-79x7-8hpr , GO-2025-4181

cvss
5.0
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 5%
public exploits
0
none known

Summary

Step CA is an online certificate authority for secure, automated certificate management for DevOps. Prior to 0.29.0, there is an improper authorization check for SSH certificate revocation. This affects deployments configured with the SSHPOP provisioner. This vulnerability is fixed in 0.29.0.

Patch / fix

  • go github.com/smallstep/certificates 0.29.0
  • smallstep step-ca 0.29.0
  • govulncheck-vulndb SLE Module for Package Hub 15 SP6, openSUSE Leap 15.6 0.0.20251209T172047-150000.1.127.1

suse advisories SUSE-SU-2025:4395-1

  • govulncheck-vulndb openSUSE Leap 16.0 0.0.20260723T184607-160000.1.1

opensuse advisories openSUSE-SU-2026:21483-1

  • step-certificates Alpine 3.24, Alpine 3.23, Alpine 3.22 0.29.0-r0

alpine advisories ALPINE-CVE-2025-66406

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2025-66406 updated cvss 5.0

github.com/smallstep/certificates: Step CA: Denial of Service via improper SSH certificate revocation authorization

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
11 mo ago

Exploit prediction

0.16% chance of exploitation in the next 30 days, higher than 5% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 5.0 CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:L/A:H
GitHub 3.1 5.0 CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:L/A:H

Affected packages

ecosystem package affected fixed in
go github.com/smallstep/certificates
<0.29.0
0.29.0

Affected products

  • smallstep certificates

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.