CSP: font-src

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since August 2016.

The HTTP Content-Security-Policy (CSP) font-src directive specifies valid sources for fonts loaded using @font-face.

CSP version	1
Directive type	Fetch directive
`default-src` fallback	Yes. If this directive is absent, the user agent will look for the `default-src` directive.

http

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

This directive may have one of the following values:

No resources of this type may be loaded. The single quotes are mandatory.

A space-separated list of source expression values. Resources of this type may be loaded if they match any of the given source expressions.

Source expressions are specified as keyword values or URL patterns: the syntax for each source expression is given in CSP Source Values.

Given this CSP header:

http

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

The following font resource loading is blocked and won't load:

html

<style>
  @font-face {
    font-family: "MyFont";
    src: url("https://not-example.com/font");
  }
  body {
    font-family: "MyFont";
  }
</style>

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

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