CVE-2026-33032

As of 2026-04-16, CVE-2026-33032 is a CVSS 9.8 (CRITICAL-severity) vulnerability. EPSS exploitation probability 9.3%. Threadlinqs Intelligence tracks 3 threats exploiting it.

Last updated: 2026-04-16

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

• Internet-Wide Reconnaissance Scans Target MCP Servers and Claude/Cursor AI-Agent Credentials — MEDIUM
• Nginx UI Authentication Bypass via Unauthenticated MCP Endpoint (CVE-2026-33032) — CRITICAL
• CVE-2026-33032 (MCPwn): nginx-ui Middleware Bypass Enabling Unauthenticated Configuration Write and Full Web Server Takeover — 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

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Enriched from CVE.org, NVD (this product uses the NVD API but is not endorsed or certified by the NVD), FIRST EPSS, CISA KEV, and GitHub Security Advisories.