CVE-2026-42221
criticalNginx UI is a web user interface for the Nginx web server.
Vendor / product: Nginxui — nginx ui
Nginx UI is a web user interface for the Nginx web server. From version 2.0.0 to before version 2.3.8, an unauthenticated network attacker can claim the initial administrator account on a fresh nginx-ui instance during the first-run setup window. The public /api/install endpoint is reachable without authentication, and the request-encryption flow only protects payload confidentiality in transit; it does not authenticate who is allowed to perform installation. A remote attacker who reaches the service before the legitimate operator can set the admin email, username, and password, causing permanent initial-instance takeover. This issue has been patched in version 2.3.8.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Affected products
Weakness classification (CWE)
Source: NVD / CISA. “NVD-CWE-Other” and “NVD-CWE-noinfo” mean NVD could not assign a specific weakness.
Mitigation & advisories
References
- https://github.com/0xJacky/nginx-ui/releases/tag/v2.3.8 security-advisories@github.com
- https://github.com/0xJacky/nginx-ui/security/advisories/GHSA-h27v-ph7w-m9fp security-advisories@github.com
- https://github.com/0xJacky/nginx-ui/security/advisories/GHSA-h27v-ph7w-m9fp 134c704f-9b21-4f2e-91b3-4a467353bcc0