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

> Attackers can issue certificates without authentication via SCEP UpdateReq, compromising trust in the Step CA system.

- **Severity:** Critical 10.0 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 19 Mar 2026
- **Updated:** 25 Mar 2026
- **Also known as:** CLEANSTART-2026-JI14170, CLEANSTART-2026-TM64574, GHSA-q4r8-xm5f-56gw, GO-2026-4775, MINI-2wg4-h9cw-h7wv, MINI-4p7v-22gr-f66j, UBUNTU-CVE-2026-30836

## What is CVE-2026-30836?

CVE-2026-30836 is a critical authentication bypass vulnerability in smallstep certificates, published on 19 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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.

Weakness: CWE-295 (Improper Certificate Validation), CWE-287 (Improper Authentication)

## Which versions are affected by CVE-2026-30836?

3 open source packages ship an affected version, including github.com/smallstep/certificates. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/smallstep/certificates` | Go | All versions | 0.30.0 |
| `github.com/smallstep/certificates` | Go | All versions | 0.30.0 |
| `github.com/smallstep/certificates` | Go | All versions | 0.30.0 |

Products: Smallstep Step-Ca.

## How do I fix CVE-2026-30836?

Upgrade github.com/smallstep/certificates to 0.30.0 or later.

## Is CVE-2026-30836 being exploited?

There is no known exploitation of CVE-2026-30836 in the wild and no public exploit code.

## Other vulnerabilities in smallstep certificates

- [CVE-2026-40097](https://insights.sbomify.com/CVE-2026-40097/): Step CA affected by an index out of bounds panic in TPM attestation EKU validation (low 3.7)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-30836 and fix it if it is affected.

What it is: CVE-2026-30836 is a critical authentication bypass vulnerability in smallstep certificates, published on 19 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-30836 in the wild and no public exploit code.

Affected packages and fixed versions:
- github.com/smallstep/certificates (Go): affected all versions; fixed in 0.30.0
- github.com/smallstep/certificates (Go): affected all versions; fixed in 0.30.0
- github.com/smallstep/certificates (Go): affected all versions; fixed in 0.30.0

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-30836/ (Markdown: https://insights.sbomify.com/CVE-2026-30836/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-30836
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-30836
- OSV: https://osv.dev/vulnerability/CVE-2026-30836

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-30836/
Summaries are generated and may contain mistakes; the official description above is the record.