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http csp directive

Content-Security-Policy: worker-src directive

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The HTTP Content-Security-Policy (CSP) worker-src directive specifies valid sources for Worker, SharedWorker, or ServiceWorker scripts.

CSP version 3
Directive type [Fetch directive](https://developer.mozilla.org/en-US/docs/Glossary/Fetch%20directive)
Fallback

If this directive is absent, the user agent will first look for the `child-src` directive, then the `script-src` directive, then finally for the `default-src` directive, when governing worker execution.

Syntax

Content-Security-Policy: worker-src 'none';
Content-Security-Policy: worker-src <source-expression-list>;

This directive may have one of the following values:

  • 'none'
    • : No resources of this type may be loaded. The single quotes are mandatory.
  • <source-expression-list>
    • : A space-separated list of source expression values. Resources of this type may be loaded if they match any of the given source expressions. For this directive, the following source expression values are applicable:

Examples

Violation cases

Given this CSP header:

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

Worker, SharedWorker, ServiceWorker are blocked and won’t load:

<script>
  let blockedWorker = new Worker("data:text/javascript,…");
  blockedWorker = new SharedWorker("https://not-example.com/");
  navigator.serviceWorker.register("https://not-example.com/sw.js");
</script>

Specifications

SpecificationsStandards references are available on the canonical MDN page.

Browser compatibility

Browser compatibilityCompatibility data is available on the canonical MDN page.

See also