CSP: worker-src

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
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

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

http

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

http

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

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

html

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

Specifications

Specification
Content Security Policy Level 3
# directive-worker-src

Browser compatibility

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See also