mcp-server-semgrep/semgrep-rules/javascript/express/security/audit/xss/mustache/explicit-unescape.yaml

MCP Server for Semgrep Integration - static code analysis with AI

rules:
- id: template-explicit-unescape
  message: >-
    Detected an explicit unescape in a Mustache template, using
    triple braces '{{{...}}}' or ampersand '&'. If external data
    can reach these locations,
    your application is exposed to a cross-site scripting (XSS)
    vulnerability. If you must do this, ensure no external data
    can reach this location.
  metadata:
    cwe:
    - "CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')"
    owasp:
    - A07:2017 - Cross-Site Scripting (XSS)
    - A03:2021 - Injection
    references:
    - https://github.com/janl/mustache.js/#variables
    - https://ractive.js.org/v0.x/0.7/mustaches#variables
    category: security
    technology:
    - express
    cwe2022-top25: true
    cwe2021-top25: true
    subcategory:
    - audit
    likelihood: LOW
    impact: MEDIUM
    confidence: LOW
  languages:
  - regex
  severity: WARNING
  paths:
    include:
    - '*.mustache'
    - '*.hbs'
    - '*.html'
  pattern-either:
  - pattern-regex: '{{{((?!include).)*?}}}'
  - pattern-regex: '{{[\\s]*&.*}}'