CSP: fenced-frame-src

Limited availability

This feature is not Baseline because it does not work in some of the most widely-used browsers.

Experimental: This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

The HTTP Content-Security-Policy (CSP) fenced-frame-src directive specifies valid sources for nested browsing contexts loaded into <fencedframe> elements.

CSP version 1
Directive type Fetch directive
Fallback If this directive is absent, the user agent will look for the frame-src directive (which falls back to the child-src directive).

Syntax

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

http
Content-Security-Policy: fenced-frame-src <source>;
Content-Security-Policy: fenced-frame-src <source> <source>;

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:

http
Content-Security-Policy: fenced-frame-src https://example.com/

The following sources will not load in a fenced frame:

  • https://not-example.com/ (domain doesn't match)
  • https://example.org/ (TLD doesn't match)

Specifications

Specification
Fenced Frame
# new-csp-directive

Browser compatibility

BCD tables only load in the browser

See also