Medium [CVE-2026-50184] @angular/service-worker: @angular/service-worker: Security flaw leads to session leaks and cached private data

Angular is a development platform for building mobile and desktop web applications using TypeScript/JavaScript and other languages. Prior to 22.0.0-rc.2, 21.2.15, 20.3.22, and 19.2.23, an issue in the @angular/service-worker package compromises the integrity of request-policy enforcement during request reconstruction.

When the Angular Service Worker intercepts network requests for matched assets, it reconstructs a new Request object using an internal helper function.

During this reconstruction process, the helper function strips explicit client-defined safety parameters: the credentials configuration (such as credentials: 'omit') and the HTTP cache mode configuration (such as cache: 'no-store'). These are reverted back to standard browser-default parameters (credentials: 'same-origin' and default HTTP cache properties).

This causes the browser to include active credentials (such as cookies or Authorization headers) on outbound requests where the client-side developer explicitly instructed they should be omitted, leading to potential session leaks.

Additionally, it causes private or non-cacheable resources to be cached by the service worker's engine, making private page states accessible or persistent inside the client's local cache post-logout. This vulnerability is fixed in 22.0.0-rc.2, 21.2.15, 20.3.22, and 19.2.23.