CSP: child-src

The HTTP Content-Security-Policy (CSP) child-src directive defines the valid sources for web workers and nested browsing contexts loaded using elements such as <frame> and <iframe>. For workers, non-compliant requests are treated as fatal network errors by the user agent.

CSP version	2
Directive type	Fetch directive
`default-src` fallback	Yes. If this directive is absent, the user agent will look for the `default-src` directive.

Syntax

One or more sources can be allowed for the child-src policy:

Content-Security-Policy: child-src <source>;
Content-Security-Policy: child-src <source> <source>;

Sources

<source> can be any one of the values listed in CSP Source Values.

Note that this same set of values can be used in all fetch directives (and a number of other directives).

Examples

Violation cases

Given this CSP header:

Content-Security-Policy: child-src https://example.com/

This <iframe> and worker are blocked and won't load:

<iframe src="https://not-example.com"></iframe>

<script>
  var blockedWorker = new Worker("data:application/javascript,...");
</script>

Specifications

Specification	Status	Comment
Content Security Policy Level 3 child-src	Working Draft	No changes.
Content Security Policy Level 2 child-src	Recommendation	Initial definition.

Browser compatibility

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