CVE-2026-61628: Lucasdillmann Nginx-Ignition

High severity, CVSS 8.1. EPSS: 0.4% chance of exploitation in the next 30 days.

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 products

• Lucasdillmann Nginx-Ignition: before 2.41.1 (fixed in 2.41.1)

Published 2026-09-21. Last modified 2026-09-23.