Apple requires all browsers to use WebKit on iPhone, so a report suggests every browser is affected by three separate leaks that can hand off information around a proxy or iCloud Private Relay.
WebKit browsers can leak data past proxies and iCloud Private Relay
When users install proxy browsers or Tor, they expect absolute privacy while navigating the web. However, one developer has discovered that three separate data leaks can occur while using WebKit browsers on iOS or macOS.
According to the Mysk blog, DNS prefetching, WebAuthn for Passkeys, and WebTransport can all reveal data about the user in spite of proxy use or iCloud Private Relay. Tor browsers, proxy apps, and Safari are affected, but VPNs are not since they’re acting at a system level to encrypt all traffic.