---
title: "CVE-2026-30836: step-ca has Unauthenticated Certificate Issuance via SCEP UpdateReq (MessageType=18)"
url: https://erroneo.us/security/cve/CVE-2026-30836/
description: "CVE-2026-30836 (github.com/smallstep/certificates (Go)): Step CA is an online certificate authority for secure, automated certificate management for DevOps.…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-03-19
date_modified: 2026-04-06
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-30836"
kev: false
cvss: 10
epss: 0.0032
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-30836: step-ca has Unauthenticated Certificate Issuance via SCEP UpdateReq (MessageType=18)

**Signal:** Critical and remotely reachable. No known exploitation yet, but it is network-reachable without credentials. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
- EPSS 0.3% , percentile 24: FIRST’s model estimates a 0.3% chance of exploitation activity in the next 30 days, higher than 24% of all scored CVEs (low). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes github.com/smallstep/certificates (Go) < 0.30.0, fixed in 0.30.0 . Check your lockfile, including transitive dependencies.

## What it is

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 packages

- Go `github.com/smallstep/certificates` < 0.30.0 → fixed: 0.30.0

## Affected products (CVE record)

- smallstep certificates: < 0.30.0

## Severity

- GitHub_M CVSS 3.1: 10 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N`
- GitHub CVSS 3.1: 10.0 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation none , automatable yes , technical impact total .
- FIRST EPSS (model of 2026-10-21): 0.32% probability of exploitation activity in the next 30 days; percentile 24.

## Sources

- [GitHub Advisory GHSA-q4r8-xm5f-56gw](https://github.com/advisories/GHSA-q4r8-xm5f-56gw)
- [CVE.org record CVE-2026-30836](https://www.cve.org/CVERecord?id=CVE-2026-30836)
- [NVD entry CVE-2026-30836](https://nvd.nist.gov/vuln/detail/CVE-2026-30836)
- [github.com](https://github.com/smallstep/certificates/security/advisories/GHSA-q4r8-xm5f-56gw)
- [github.com](https://github.com/smallstep/certificates/commit/e6da031d5125cfd99fe9a26f74bb41e4dacca4ef)
- [github.com](https://github.com/smallstep/certificates/releases/tag/v0.30.0-rc7)

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Source page: https://erroneo.us/security/cve/CVE-2026-30836/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt