mcp-server-semgrep/semgrep-rules/javascript/browser/security/dom-based-xss.yaml

MCP Server for Semgrep Integration - static code analysis with AI

rules:
- id: dom-based-xss
  message: >-
    Detected possible DOM-based XSS. This occurs because a portion of the URL is being used
    to construct an element added directly to the page. For example, a malicious actor could
    send someone a link like this: http://www.some.site/page.html?default=<script>alert(document.cookie)</script>
    which would add the script to the page.
    Consider allowlisting appropriate values or using an approach which does not involve the URL.
  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://owasp.org/www-community/attacks/DOM_Based_XSS
    category: security
    technology:
    - browser
    cwe2022-top25: true
    cwe2021-top25: true
    subcategory:
    - audit
    likelihood: LOW
    impact: LOW
    confidence: LOW
  languages:
  - javascript
  - typescript
  severity: ERROR
  pattern-either:
  - pattern: document.write(<... document.location.$W ...>)
  - pattern: document.write(<... location.$W ...>)