Nginx UI: Unauthenticated MCP Endpoint Allows Remote Nginx Takeover
97Vexday Risk Score
Patch now. It exploitation observed by VulnCheck and has a working public exploit.
ssvc Actcvss 9.8epss 38%
from disclosure to weapon18 days
Published on NVDMar 30
1st PoC+18d
VulnCheck+14d
exploitation probability
38%top 2% of all CVEs
observed exploitation
yesVulnCheck
1 public exploit(s)
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:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Affected products
0xJacky · nginx-uipublic PoCs found — 1
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