Cloudanix VulnDB

CVE-2026-42221

High · 8.1

CVSS

8.1

EPSS

1.6%

Published

May 4, 2026

CISA due date

—

The record

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.

Affected packages

Ecosystem Package Introduced Fixed

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