mcp-server-semgrep/semgrep-rules/python/flask/security/xss/audit/template-unquoted-attribute-var.yaml

MCP Server for Semgrep Integration - static code analysis with AI

rules:
- id: template-unquoted-attribute-var
  message: >-
    Detected a unquoted template variable as an attribute. If unquoted, a
    malicious actor could inject custom JavaScript handlers. To fix this, add
    quotes around the template expression, like this: "{{ $...VAR }}".
  metadata:
    cwe:
    - "CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')"
    owasp:
    - A07:2017 - Cross-Site Scripting (XSS)
    - A03:2021 - Injection
    references:
    - https://flask.palletsprojects.com/en/1.1.x/security/#cross-site-scripting-xss
    category: security
    technology:
    - flask
    cwe2022-top25: true
    cwe2021-top25: true
    subcategory:
    - audit
    likelihood: LOW
    impact: MEDIUM
    confidence: LOW
  languages:
  - generic
  paths:
    include:
    - '*.html'
    - '*.py'
  severity: WARNING
  patterns:
    - pattern: ={{$...VAR}}
    - pattern-inside: |
        <$TAG ... >
    - metavariable-pattern:
        metavariable: $...VAR
        pattern-either:
          - pattern: |
              request.$VALUE.get(...)
          - pattern: |
              request.$VALUE['...']
          - patterns: 
              - pattern: $REQ
              - pattern-either:
                - pattern-inside: |
                    $REQ = request.$VALUE.get(...)
                    ... 
                - pattern-inside: |
                    $REQ = request.$VALUE['...']
                    ... 
  fix: |
    ="{{$...VAR}}"