Apple iCloud Private Relay Can Expose Real IPs Through WebKit Proxy Bypasses

Researchers Talal Haj Bakry and Tommy Mysk discovered a privacy issue in Apple's iCloud Private Relay that can expose a user's real IP address due to WebKit proxy bypasses. The vulnerability stems from three WebKit features—DNS prefetching, WebAuthn Related Origin Requests, and WebTransport—which send traffic directly from the device, bypassing the proxy configuration. This allows websites, particularly those using WebAuthn for passkeys, to view a user's real IP address even when Private Relay is enabled, without requiring user interaction or passkey usage.

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