CVE-2025-66406: step-ca Has Improper Authorization Check for SSH Certificate Revocation

December 3, 2025 (updated December 4, 2025)

A security fix is now available for Step CA that resolves a vulnerability affecting deployments configured with the SSHPOP provisioner. All operators running these provisioners should upgrade to the latest release (v0.29.0) immediately.

The issue was discovered and responsibly disclosed by a research team during a security review. There is no evidence of active exploitation.

To limit exploitation risk during a coordinated disclosure window, we are withholding detailed technical information for now. A full write-up will be published in several weeks.

References

github.com/advisories/GHSA-j7c9-79x7-8hpr
github.com/smallstep/certificates
github.com/smallstep/certificates/security/advisories/GHSA-j7c9-79x7-8hpr
nvd.nist.gov/vuln/detail/CVE-2025-66406

Code Behaviors & Features

Detect and mitigate CVE-2025-66406 with GitLab Dependency Scanning

Secure your software supply chain by verifying that all open source dependencies used in your projects contain no disclosed vulnerabilities. Learn more about Dependency Scanning →