CVE-2026-61628

HIGH 8.1

nginx ignition has Unauthenticated Admin Account Creation via Onboarding Race Condition

CVSS Score

8.1

EPSS Score

0.0%

EPSS Percentile

0th

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.

CWE	CWE-362
Vendor	lucasdillmann
Product	nginx-ignition
Published	Sep 21, 2026
Last Updated	Sep 21, 2026

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CVSS v3 Breakdown

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

Attack Vector

Network

Attack Complexity

High

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Affected Versions

lucasdillmann / nginx-ignition

< 2.41.1

References

NVD ↗ CVE.org ↗ EPSS Data ↗

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