What’s Vulnerable › Vulnerabilities

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

• Severity: high (CVSS 8.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-09-21 · updated 2026-09-23
• Weakness: CWE-362

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.

Affected products

• lucasdillmann nginx-ignition: before 2.41.1

References

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

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