CVE-2026-61628

nginx ignition has Unauthenticated Admin Account Creation via Onboarding Race Condition

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.

Affected

lucasdillmann · nginx-ignition

CVSS v3.1 GITHUB

8.1 HIGHCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS

0.43% chance of exploitation in the next 30 days, 36th percentile

Published

2026-09-21

Proof-of-concept exploits (2)

• advisories/GHSA-pxcx-fv34-x9p5
• abraxas/CVE-2026-616280★ · 2026-10-07

References

• CVE Record
• NVD entry