# CVE-2026-61628: nginx ignition has Unauthenticated Admin Account Creation via Onboarding Race Condition

> Unauthenticated attackers can create admin accounts via a race condition in nginx ignition's onboarding endpoint, leading to full system compromise.

- **Severity:** High 8.1 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 21 Sep 2026
- **Updated:** 21 Sep 2026
- **Also known as:** GHSA-pxcx-fv34-x9p5, GO-2026-6540

## What is CVE-2026-61628?

CVE-2026-61628 is a high-severity vulnerability in lucasdillmann nginx-ignition, published on 21 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

nginx ignition is a user interface for the nginx web server. Prior to version 2.41.1, `POST /api/users/onboarding/finish` is registered as anonymous (unauthenticated) and creates a user with full ReadWrite admin permissions. Because the handler uses a check-then-act (TOCTOU) pattern between the "onboarding already completed?" check and the user-creation write, with no atomic guard, a remote unauthenticated attacker who can reach an instance in its pre-onboarding state can create an administrator account for themselves — and concurrent requests can create multiple admin accounts in a single race. Version 2.41.1 patches the issue.

Weakness: CWE-362 (Concurrent Execution using Shared Resource with Improper Synchronization)

## Which versions are affected by CVE-2026-61628?

3 open source packages ship an affected version, including github.com/lucasdillmann/nginx-ignition.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/lucasdillmann/nginx-ignition` | Go | All versions | None |
| `github.com/lucasdillmann/nginx-ignition` | Go | All versions | 0.0.0-20260621194639-0586b4e55ab |
| `github.com/lucasdillmann/nginx-ignition` | Go | All versions | 0.0.0-20260621194639-0586b4e55ab |

## How do I fix CVE-2026-61628?

Upgrade github.com/lucasdillmann/nginx-ignition to 0.0.0-20260621194639-0586b4e55ab or later.

## Is CVE-2026-61628 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-61628 exists.

Public exploit code:

- CVE-2026-61628 - nginx-ignition - High 8.1 - Unauthenticated Privilege Escalation (Administrator Account Creation) (github_poc): https://github.com/abraxas/CVE-2026-61628

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-61628 and fix it if it is affected.

What it is: CVE-2026-61628 is a high-severity vulnerability in lucasdillmann nginx-ignition, published on 21 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-61628 exists.

Affected packages and fixed versions:
- github.com/lucasdillmann/nginx-ignition (Go): affected all versions; no fix listed
- github.com/lucasdillmann/nginx-ignition (Go): affected all versions; fixed in 0.0.0-20260621194639-0586b4e55ab
- github.com/lucasdillmann/nginx-ignition (Go): affected all versions; fixed in 0.0.0-20260621194639-0586b4e55ab

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-2026-61628/ (Markdown: https://insights.sbomify.com/CVE-2026-61628/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-61628
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-61628
- OSV: https://osv.dev/vulnerability/CVE-2026-61628

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-61628/
Summaries are generated and may contain mistakes; the official description above is the record.