Content-Security-Policy: worker-src directive
Baseline
Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since May 2022.
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
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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
| Specification |
|---|
| Content Security Policy Level 3 # directive-worker-src |
Browser compatibility
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worker-src
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Legend
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- Full support
- Full support
- See implementation notes.