CVE-2026-102878: mcp-chrome-bridge (hangwin/mcp-chrome) <= 1.0.31 - CORS Origin Bypass (CSWSH)

id: CVE-2026-102878

info:
  name: mcp-chrome-bridge (hangwin/mcp-chrome) <= 1.0.31 - CORS Origin Bypass (CSWSH)
  author: carfeii
  severity: high
  description: |
    mcp-chrome-bridge <=1.0.31 uses origin.startsWith for CORS, so origins like http://127.0.0.1.evil.com are wrongly allowed, letting attackers bypass CORS and access the local server.
  remediation: |
    Update to the latest version beyond 1.0.31.
  impact: |
    Any website can bypass the server's CORS allowlist and make credentialed cross-origin requests to the local native-server, enabling unauthorized use of the exposed browser-automation tools (navigation, script execution, cookie/session access, screenshots) from any open browser tab.
  reference:
    - https://github.com/hangwin/mcp-chrome/issues/384
    - https://github.com/hangwin/mcp-chrome/pull/383
    - https://www.vulncheck.com/advisories/mcp-chrome-bridge-through-1.0.31-cors-origin-bypass
    - https://nvd.nist.gov/vuln/detail/CVE-2026-102878
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N
    cvss-score: 8.1
    cve-id: CVE-2026-102878
    epss-score: 0.00798
    epss-percentile: 0.56773
    cwe-id: CWE-346
  metadata:
    verified: true
    max-request: 2
    vendor: hangwin
    product: mcp-chrome-bridge
    shodan-query: html:"Chrome MCP"
    fofa-query: body="Chrome MCP"
  tags: cve,cve2026,mcp-chrome,cors,cswsh,misconfig

flow: http(1) && http(2)

http:
  - raw:
      - |
        GET /ping HTTP/1.1
        Host: {{Hostname}}

    matchers:
      - type: dsl
        dsl:
          - 'status_code == 200'
          - 'contains(tolower(body), "pong")'
        condition: and
        internal: true

  - raw:
      - |
        GET /ping HTTP/1.1
        Host: {{Hostname}}
        Origin: {{cors_origin}}

    payloads:
      cors_origin:
        - "http://127.0.0.1.{{rand_base(6)}}.com"

    matchers:
      - type: dsl
        dsl:
          - 'status_code == 200'
          - 'contains(tolower(header), "access-control-allow-origin: {{tolower(cors_origin)}}")'
          - 'contains(tolower(header), "access-control-allow-credentials: true")'
        condition: and
# digest: 4a0a0047304502207cb5471462cf48215267b229c9cdf11023068e7992df6b452c2c1ea98ed51f3102210088a4706ec2d521cac5554ba002e000c82a81552ca96ac24e54b2b46ceebc4804:922c64590222798bb761d5b6d8e72950

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