VULNpocalypse

CVE-2026-33032: Nginx UI: Unauthenticated MCP Endpoint Allows Remote Nginx Takeover

Advisory generated from the CVE record, CISA, Exploit Observer and VEDAS: what it is, whether it is exploited, who is affected, and how to fix and detect it.

Generated by VEDAS. Scores as of 2026-11-01 19:19 UTC. Rebuilt every few hours from cve-scores, CISA KEV and vedas-signatures. How this works and its limits.

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 /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.

Description quoted from the CVE record (assigned by GitHub_M, published 2026-03-30).

Weakness: CWE-306: Missing Authentication for Critical Function

How it can be exploited

Exploitable over the network with low attack complexity needing no privileges and no user interaction. Impact: confidentiality high, integrity high, availability high. CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CISA assessment (SSVC): CISA assesses that a public proof of concept exists. Automatable: yes. Technical impact: total.

Public exploit evidence (Exploit Observer)

Also known as: BDU:2026-04537, EUVD-2026-17158, GHSA-76pm-mq2q-9gcr, GHSA-cf23-7qxj-xmhr, GHSA-h6c2-x2m2-mwhf

VEDAS cluster: VEDAS:FREELYFLOWING

Exploit Observer links 10 pieces of public exploit code or detection modules that name this CVE or one of its aliases.

Exploit code and modules (10)

Code that names this CVE. A repository can be a working exploit, a scanner, a fake or malware; read it before running anything.

Research and write-ups (1)

Vulnerability databases and vendor advisories (9)

Catalogue entries, not exploit evidence.

4 more references returned by Exploit Observer did not name this CVE or an alias, so they are left out.

VEDAS data as of 2026-11-01T17:12 UTC; fetched 2026-11-02.

Live scores

EPSS
0.353
likely to be attacked soon
VEDAS
0.981
strong exploit evidence
On CISA KEV
Not listed
Detection rule
Nuclei · Suricata

Who is affected

ProductAffectedNot affected
0xJacky nginx-uiversion <= 2.3.5Not stated

Version ranges exactly as the CVE record states them. “Before X” means X is the first fixed version.

Exploit Observer also maps it to: nginxui nginx_ui, сообщество_свободного_программного_обеспечения nginx_ui.

How to fix it

No fixed version or vendor advisory is listed in the CVE record yet. Watch the vendor’s security page.

How to detect it

Nuclei template (active check)

Nginxui - Missing Authentication

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.

Name and description quoted from the template, written by VEDAS.

The template sends 1 request (POST /mcp_message); it decides using status, word matchers. Severity in the template: critical. Marked as not yet verified against a live vulnerable target.

Run it against a host you own or are authorised to test:

bash
nuclei -u https://your-host -t CVE-2026-33032.yaml
Show the template (45 lines)
yaml
id: CVE-2026-33032

info:
  name: "Nginxui - Missing Authentication"
  author: vedas-arpsyndicate
  severity: critical
  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.
  reference:
    - https://www.exploit.observer/?keyword=CVE-2026-33032&match=exact
    - https://subdomain.center/?engine=ammonites&keyword=nginxui&match=exact
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
    cvss-score: 9.8
    cve-id: CVE-2026-33032
    cwe-id: CWE-306
  metadata:
    verified: false
  tags: cve,cve2026,nginx-ui,mcp,unauth,misconfig,vkev,nginxui
variables:
  string: "{{to_lower(rand_text_alpha(5))}}"

http:
  - raw:
      - |
        POST /mcp_message HTTP/1.1
        Host: {{Hostname}}
        Content-Type: application/json

        {"jsonrpc":"2.0","method":"initialize","params":{"protocolVersion":"2024-11-05","capabilities":{},"clientInfo":{"name":"{{string}}","version":"1.0"}},"id":1}

    matchers-condition: and
    matchers:
      - type: word
        part: body
        words:
          - '{"jsonrpc":'
          - '"message":'
          - '"id":'
        condition: and

      - type: status
        status:
          - 400

CVE-2026-33032.yaml on GitHub

Suricata rules (network detection)

1 rule that alert on traffic matching this exploit: VEDAS CVE-2026-33032 Nginxui - Missing Authentication. Add them to your Suricata rule set and reload.

Show the rules
suricata
alert http $EXTERNAL_NET any -> $HTTP_SERVERS $HTTP_PORTS (msg:"VEDAS CVE-2026-33032 Nginxui - Missing Authentication"; flow:established,to_server; http.uri; content:"/mcp_message"; nocase; fast_pattern; classtype:web-application-attack; reference:cve,CVE-2026-33032; reference:url,https://www.exploit.observer/?keyword=CVE-2026-33032&match=exact; reference:url,https://subdomain.center/?engine=ammonites&keyword=nginxui&match=exact; sid:1010430; rev:1;)

CVE-2026-33032.rules on GitHub

Advisories on this CVE

References

Other references

Other databases

Where this comes from

This advisory is generated automatically by VEDAS from: CVE.org record, cve-scores (EPSS and VEDAS), Exploit Observer, vedas-signatures. Text in quotes is reproduced from the source; everything else is a fixed template filled with source fields. Nothing here is written by a language model. Check the vendor advisory before acting, and read how VEDAS and Exploit Observer work, and their limits.