CVE-2025-66406: Smallstep Certificates

Medium severity, CVSS 5.0. EPSS: 0.2% chance of exploitation in the next 30 days.

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.

Affected products

• Smallstep Certificates: before 0.29.0 (fixed in 0.29.0)

Published 2025-12-03. Last modified 2026-06-17.