Nginx UI - Broken Access Control

id: CVE-2026-33032

info:
  name: Nginx UI - Broken Access Control
  author: DhiyaneshDk
  severity: critical
  description: |
    Network attackers can fully control nginx service, including config modification and service restart, leading to complete service takeover.
  impact: |
    An unauthenticated attacker with a valid MCP session ID can inject arbitrary nginx configurations,create reverse proxies for credential theft, and achieve remote code execution via nginx config primitives.
  remediation: Upgrade to nginx-ui v2.3.4 or later which adds AuthRequired() to /mcp_message.
  reference:
    - https://github.com/0xJacky/nginx-ui/security/advisories/GHSA-h6c2-x2m2-mwhf
    - https://github.com/0xJacky/nginx-ui/commit/413dc631
    - https://nvd.nist.gov/vuln/detail/CVE-2026-33032
  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
    epss-score: 0.38477
    epss-percentile: 0.98394
    cwe-id: CWE-306
  metadata:
    verified: true
    max-request: 1
    product: nginx-ui
    shodan-query: http.title:"Nginx UI"
    fofa-query: title="Nginx UI"
  tags: cve,cve2026,nginx-ui,mcp,unauth,misconfig,vkev

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
# digest: 4a0a00473045022100c02335387bce98f782ffe3e30732e25a10369c6fdfe11701cc0bac76e78cdc7f02202e779a1fbc279b261ac651a8e3ff14fc92552611902e019c66656a92e0ce2ebd:922c64590222798bb761d5b6d8e72950