CVE-2026-33032

CRITICAL EXPLOITED NUCLEI LAB

Nginx UI: Unauthenticated MCP Endpoint Allows Remote Nginx Takeover

Title source: cna
STIX 2.1

Exploitation Summary

CVE-2026-33032 has been observed exploited in the wild (reported by VulnCheck KEV). EIP tracks 3 public exploits from researchers including keraattin, Shreda, Twinson333. A Nuclei detection template is also available.

AI-analyzed exploit summary This repository provides a non-destructive detection tool for CVE-2026-33032, an authentication bypass vulnerability in nginx-ui versions prior to 2.3.4. The tool checks for the presence of the vulnerability by attempting to list MCP tools without authentication.

Description

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.

Exploits (3)

nomisec SCANNER
by keraattin · poc
https://github.com/keraattin/CVE-2026-33032

This repository provides a non-destructive detection tool for CVE-2026-33032, an authentication bypass vulnerability in nginx-ui versions prior to 2.3.4. The tool checks for the presence of the vulnerability by attempting to list MCP tools without authentication.

Classification
Scanner 100%
Attack Type
Auth Bypass
Complexity
Trivial
Reliability
Reliable
Target: nginx-ui < 2.3.4
No auth needed
Prerequisites: Network access to the nginx-ui instance
devstral-2 · analyzed Apr 18, 2026 Full analysis →
nomisec WORKING POC
by Shreda · remote
https://github.com/Shreda/CVE-2026-33032-nginx-ui-vuln-lab

This repository contains a functional exploit for CVE-2026-33032, which chains with CVE-2026-27944 to achieve unauthenticated remote code execution (RCE) in nginx-ui v2.3.1. The exploit leverages an unauthenticated backup endpoint to extract credentials and then abuses a missing authentication middleware in the MCP message handler to modify nginx configurations and reload the service.

Classification
Working Poc 100%
Attack Type
Rce
Complexity
Moderate
Reliability
Reliable
Target: nginx-ui v2.3.1
No auth needed
Prerequisites: Docker and Docker Compose for lab setup · Python 3.10+ for exploit execution
devstral-2 · analyzed Apr 17, 2026 Full analysis →
nomisec SCANNER
by Twinson333 · poc
https://github.com/Twinson333/cve-2026-33032-scanner

This repository contains a non-destructive scanner for CVE-2026-33032, an authentication bypass vulnerability in nginx-ui's MCP endpoint. The scanner detects the vulnerability by testing read-only MCP tools without authentication.

Classification
Scanner 100%
Attack Type
Auth Bypass
Complexity
Moderate
Reliability
Reliable
Target: nginx-ui (versions with MCP integration)
No auth needed
Prerequisites: nginx-ui installation with MCP integration · network access to the target
devstral-2 · analyzed Apr 08, 2026 Full analysis →

Nuclei Templates (1)

Nginx UI - Broken Access Control
CRITICALVERIFIEDby DhiyaneshDk
Shodan: http.title:"Nginx UI"
FOFA: title="Nginx UI"

References (2)

Core 2

Scores

CVSS v3 9.8
EPSS 0.1374
EPSS Percentile 94.5%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CISA SSVC

Vulnrichment
Exploitation poc
Automatable yes
Technical Impact total

Lab Environment

COMMUNITY
Community Lab
docker pull uozi/nginx-ui:v2.3.1

Details

VulnCheck KEV 2026-04-13
CWE
CWE-306
Status published
Products (3)
0xJacky/Nginx-UI 0Go
0xJacky/nginx-ui <= 2.3.5
nginxui/nginx_ui < 2.3.5
Published Mar 30, 2026
Tracked Since Mar 31, 2026