mcp-server-semgrep/semgrep-rules/ruby/rails/security/audit/xss/templates/var-in-href.yaml

MCP Server for Semgrep Integration - static code analysis with AI

rules:
- id: var-in-href
  message: >-
    Detected a template variable used in an anchor tag with
    the 'href' attribute. This allows a malicious actor to
    input the 'javascript:' URI and is subject to cross-
    site scripting (XSS) attacks. If using a relative URL,
    start with a literal forward slash and concatenate the URL,
    like this: href='/<%= link =>'. You may also consider setting
    the Content Security Policy (CSP) header.
  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://flask.palletsprojects.com/en/1.1.x/security/#cross-site-scripting-xss#:~:text=javascript:%20URI
    - https://github.com/pugjs/pug/issues/2952
    category: security
    technology:
    - rails
    cwe2022-top25: true
    cwe2021-top25: true
    subcategory:
    - audit
    likelihood: LOW
    impact: MEDIUM
    confidence: LOW
  languages:
  - generic
  paths:
    include:
    - '*.erb'
  severity: WARNING
  pattern-either:
  - pattern: <a ... href = "<%= ... %>" ... >
  - pattern: <a ... href = '<%= ... %>' ... >