CVE-2026-30836: Step CA: Unauthenticated Certificate Issuance via SCEP UpdateReq (MessageType=18)

Severity: critical (CVSS 10.0 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-03-19 · updated 2026-06-17
Weakness: CWE-287

Description

Step CA is an online certificate authority for secure, automated certificate management for DevOps. Versions 0.30.0-rc6 and below do not safeguard against unauthenticated certificate issuance through the SCEP UpdateReq. This issue has been fixed in version 0.30.0.

Affected products

smallstep Step-CA: before 0.30.0; 0.30.0-rc1, 0.30.0-rc2, 0.30.0-rc3, 0.30.0-rc4, 0.30.0-rc5, 0.30.0-rc6 — fixed in 0.30.0
Go Github.Com/Smallstep/Certificates: before 0.30.0 — fixed in 0.30.0

How to fix

Upgrade to a fixed version: smallstep Step-CA 0.30.0; Go Github.Com/Smallstep/Certificates 0.30.0. Check the vendor advisory for mitigations.

References

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