mcp-server-semgrep/semgrep-rules/ruby/rails/security/audit/xss/templates/alias-for-html-safe.yaml

MCP Server for Semgrep Integration - static code analysis with AI

rules:
- id: alias-for-html-safe
  message: >-
    The syntax `<%== ... %>` is an alias for `html_safe`. This means the
    content inside these tags will be rendered as raw HTML. This may expose
    your application to cross-site scripting. If you need raw HTML, prefer
    using the more explicit `html_safe` and be sure to correctly sanitize
    variables using a library such as DOMPurify.
  metadata:
    cwe:
    - "CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')"
    references:
    - https://medium.com/sumone-technical-blog/a-pretty-way-to-unescape-html-in-a-ruby-on-rails-application-efc22b850027
    - https://stackoverflow.com/questions/4251284/raw-vs-html-safe-vs-h-to-unescape-html#:~:text===
    category: security
    technology:
    - rails
    owasp:
    - A07:2017 - Cross-Site Scripting (XSS)
    - A03:2021 - Injection
    cwe2022-top25: true
    cwe2021-top25: true
    subcategory:
    - audit
    likelihood: LOW
    impact: MEDIUM
    confidence: LOW
  languages: [generic]
  paths:
    include:
    - '*.erb'
  severity: WARNING
  patterns:
  - pattern: <%== ... %>
  - pattern-not: <%== $...A.to_json %>