CVE

CVE-2026-42221

8.1

CVSShigh

Exploitable remotely over the internet · no authentication required.

Description

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.

Attack Vector

Network

Privileges Req.

None

User Interaction

None

nginx-ui

Updated Nov 10, 2026View on NVD →

S4E scanner

highProduct Based Web Vulnerabilities~10 seconds

Nginx UI <= 2.3.7 - Unauthenticated Installer Exposure

Nginx UI 2.0.0 to 2.3.8 contains an authentication bypass caused by unauthenticated access to /api/install during first-run setup, letting remote attackers claim the initial admin account, exploit requires attacker to access the service before legitimate operator. References: https://github.com/0xJacky/nginx-ui/security/advisories/GHSA-h27v-ph7w-m9fp https://github.com/0xJacky/nginx-ui/releases/tag/v2.3.8 https://nvd.nist.gov/vuln/detail/CVE-2026-42221 Remediation: Upgrade to version 2.3.8 or later.

10 assets checked · domain, subdomain, ipv4

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CVE history: nginx-ui

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