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HIGH

CVE-2026-61628

nginx ignition has Unauthenticated Admin Account Creation via Onboarding Race Condition

CVSS v3

8.1

HIGH

EPSS Score

0.4 %

exploit probability, as of 2026-09-28

CISA KEV

No

known exploited

Exploitation

poc

SSVC status

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

Technical details

Published
2026-09-21
Last Modified
2026-09-21

Frequently asked questions

What is CVE-2026-61628?

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

Is CVE-2026-61628 actively exploited?

A proof-of-concept exploit exists for CVE-2026-61628, but active exploitation has not been confirmed at this time.

What is the CVSS score for CVE-2026-61628?

CVE-2026-61628 has a CVSS v3 base score of 8.1 (HIGH severity).

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