---
title: "CVE-2026-33032: nginx-ui's Unauthenticated MCP Endpoint Allows Remote Nginx Takeover"
url: https://erroneo.us/security/cve/CVE-2026-33032/
description: "CVE-2026-33032 (github.com/0xJacky/Nginx-UI (Go)): Nginx UI is a web user interface for the Nginx web server. In versions 2.3.5 and prior, the nginx-ui MCP…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-03-30
date_modified: 2026-04-27
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-33032"
kev: false
cvss: 9.8
epss: 0.02523
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-33032: nginx-ui's Unauthenticated MCP Endpoint Allows Remote Nginx Takeover

**Signal:** Critical and remotely reachable. No known exploitation yet, but it is network-reachable without credentials. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Not in CISA KEV , but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
- EPSS 2.5% , percentile 85: FIRST’s model estimates a 2.5% chance of exploitation activity in the next 30 days, higher than 85% of all scored CVEs (elevated). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes github.com/0xJacky/Nginx-UI (Go) <= 1.99, no fixed version listed . Check your lockfile, including transitive dependencies.

## What it is

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 /mcpmessage. While /mcp requires both IP whitelisting and authentication (AuthRequired() middleware), the /mcpmessage 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 packages

- Go `github.com/0xJacky/Nginx-UI` <= 1.99 → fixed: none listed

## Affected products (CVE record)

- 0xJacky nginx-ui: <= 2.3.5

## Severity

- GitHub_M CVSS 3.1: 9.8 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`
- GitHub CVSS 3.1: 9.8 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation poc , automatable yes , technical impact total .
- FIRST EPSS (model of 2026-10-21): 2.52% probability of exploitation activity in the next 30 days; percentile 85.

## Sources

- [GitHub Advisory GHSA-h6c2-x2m2-mwhf](https://github.com/advisories/GHSA-h6c2-x2m2-mwhf)
- [CVE.org record CVE-2026-33032](https://www.cve.org/CVERecord?id=CVE-2026-33032)
- [NVD entry CVE-2026-33032](https://nvd.nist.gov/vuln/detail/CVE-2026-33032)
- [github.com](https://github.com/0xJacky/nginx-ui/security/advisories/GHSA-h6c2-x2m2-mwhf)
- [websec.net](https://websec.net/blog/cve-2026-33032-unauthenticated-nginx-ui-mcp-takeover-69e1200f9fceb1f3fbe9c47f)
- [github.com](https://github.com/0xJacky/nginx-ui/blob/f89f8ff8223478988f7ed49bf1d3dbf2de44bf92/internal/middleware/ip_whitelist.go#L11-L26)
- [github.com](https://github.com/0xJacky/nginx-ui/blob/f89f8ff8223478988f7ed49bf1d3dbf2de44bf92/mcp/router.go#L9-L17)

---
Source page: https://erroneo.us/security/cve/CVE-2026-33032/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt