Affected versions of this package are vulnerable to Use of Cache Containing Sensitive Information via the HttpTransferCache process. An attacker can access sensitive user-specific information by exploiting a scenario where a child HttpClient delegates requests to a parent client that injects authentication credentials, resulting in authenticated responses being cached and served to unauthorized users. This is only exploitable if all of the following conditions are met: Server-Side Rendering (SSR) with hydration is enabled, a hierarchical HttpClient configuration with withRequestsMadeViaParent() is used, authentication credentials are injected by a parent interceptor, and SSR HTML responses are cached by a shared caching layer (such as a CDN or reverse proxy).
Workaround
This vulnerability can be mitigated by attaching authentication credentials directly within the child client, applying explicit cache filters on the child client to exclude sensitive endpoints, or disabling HTTP transfer cache for routes handling user-authenticated data and ensuring SSR responses set appropriate cache-control headers.
Remediation
Upgrade @angular/common to version 20.3.28, 21.2.20, 22.1.1 or higher.