Background Fetch requests now require that the service worker's origin has the necessary Local Network Access (LNA) permission to send requests to local or loopback servers. This aligns Chromium's implementation with the intent of the Background Fetch spec, which states that such requests go through the Fetch spec and have the same security policies applied to them including, in this case, LNA checks. This prevents sites from bypassing LNA checks by using [Background Fetch spec](https://wicg.github.io/background-fetch/) instead of regular [Fetch](https://fetch.spec.whatwg.org/). For enterprises, you can use existing LNA enterprise policies in the same way you previously would have for regular Fetch API requests from service workers: - [LocalNetworkAccessRestrictionsTemporaryOptOut](https://chromeenterprise.google/policies/#LocalNetworkAccessRestrictionsTemporaryOptOut) - [LocalNetworkAccessAllowedForUrls](https://chromeenterprise.google/policies/#LocalNetworkAccessAllowedForUrls) - [LoopbackNetworkAllowedForUrls](https://chromeenterprise.google/policies/#LoopbackNetworkAllowedForUrls) - [LocalNetworkAccessPermissionsPolicyDefaultEnabled](https://chromeenterprise.google/policies/#LocalNetworkAccessPermissionsPolicyDefaultEnabled) - [LocalNetworkAccessIpAddressSpaceOverrides](https://chromeenterprise.google/policies/#LocalNetworkAccessIpAddressSpaceOverrides)).
This fixes a security issue where Background Fetch unintentionally bypasses security policies such as Local Network Access checks.