useIframeSandbox (HTML)

Summary

Rule available since: v2.4.12
Diagnostic Category: lint/nursery/useIframeSandbox
This rule doesn’t have a fix.
The default severity of this rule is warning.

How to configure

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{
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  "linter": {
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    "rules": {
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      "nursery": {
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        "useIframeSandbox": "error"
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      }
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    }
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  }
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}

Description

Require the sandbox attribute on <iframe> elements.

An iframe can run content from another document. The sandbox attribute restricts capabilities such as scripts, forms, navigation, and popups. An empty sandbox applies all restrictions; individual allow-* tokens restore only the capabilities the frame needs.

See MDN’s iframe sandbox reference.

Examples

Invalid

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<iframe src="https://example.com"></iframe>

code-block.html:1:1 lint/nursery/useIframeSandbox ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ⚠ Iframe doesn't have the sandbox attribute.
  
  > 1 │ <iframe src="https://example.com"></iframe>
      │ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    2 │ 
  
  ℹ The sandbox attribute enables an extra set of restrictions for the content in the iframe, protecting against malicious scripts and other security threats.
  
  ℹ Provide a sandbox attribute when using iframe elements.
  
  ℹ This rule belongs to the nursery group, which means it is not yet stable and may change in the future. Visit https://biomejs.dev/linter/#nursery for more information.

Valid

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<iframe src="https://example.com" sandbox="allow-popups"></iframe>