Nginx UI is a web user interface for the Nginx web server. From 2.0.0 until 2.5.0, AuthRequired accepts a browser-managed token cookie as an API credential after the front end stores the JWT in that cookie. Because management endpoints do not universally require a CSRF token or perform Origin or Referer validation, a remote attacker can induce a logged-in administrator's browser to submit authenticated cross-site state-changing requests, including POST /api/configs. The attack requires an administrator account without OTP/Passkey or a target endpoint that does not require secure-session proof.