CVE-2026-33032

Nginx UI is a web user interface for the Nginx web server. In versions 2.3.5 and prior, the nginx-ui MCP (Model Context Protocol) integration exposes two HTTP endpoints: /mcp and /mcp_message. While /mcp requires both IP whitelisting and authentication (AuthRequired() middleware), the /mcp_message endpoint only applies IP whitelisting - and the default IP whitelist is empty, which the middleware treats as "allow all". This means any network attacker can invoke all MCP tools without authentication, including restarting nginx, creating/modifying/deleting nginx configuration files, and triggering automatic config reloads - achieving complete nginx service takeover. At time of publication, there are no publicly available patches.

Affected products

Nginx, Nginx-Ui

Nginxui Nginx Ui

≤ 2.3.5

Fix

Available

CVSS 3.1

9.8 CRITICAL

EPSS

38.5% (98th percentile)

Weakness

CWE-306

NVD status

Modified

Published

2026-03-30