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.
CVSS v3 vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weaknesses (CWE)
CWE-306
Threats tracking this CVE
- CVE-2026-33032 (MCPwn): nginx-ui Middleware Bypass Enabling Unauthenticated Configuration Write and Full Web Server Takeover — CRITICAL
- Nginx UI Authentication Bypass via Unauthenticated MCP Endpoint (CVE-2026-33032) — CRITICAL
References
- https://github.com/0xJacky/nginx-ui/security/advisories/GHSA-h6c2-x2m2-mwhf
- https://websec.net/blog/cve-2026-33032-unauthenticated-nginx-ui-mcp-takeover-69e1200f9fceb1f3fbe9c47f