Researchers have uncovered flaws in Apple's Private Relay that can reveal a user's real IP address even while the opt-in privacy feature is active in Safari. The discovery was first reported by 404 Media, with researchers Talal Haj Bakry and Tommy Mysk detailing the issue in a blog post.
The problem stems from three features in WebKit, Apple's browser engine used by all browsers in iOS, according to the researchers. A website can make a special request for a Passkey credential origin that happens outside the usual browser stack, which means iCloud Private Relay doesn't protect that traffic and your real IP address can be exposed.
Android Authority reports the WebKit flaw lets websites bypass iCloud Private Relay during passkey requests, so system-level requests bypass the protection entirely.
To help users verify whether their IP address is exposed, the researchers set up a test website where anyone can check if their real IP address leaks, even if they use Private Relay. In a test on Tuesday, TechCrunch verified the site revealed its real IP address.
Android Authority notes tests reportedly confirm the site returns the actual IP address of a device with iCloud Private Relay enabled.
Private Relay is only available to iCloud+ subscribers and is not like a VPN, which protects someone's IP address at the system level. The feature only works while using Safari, so traffic outside the browser bypasses it.
Macworld explains that because passkey requests technically happen outside the browser, they aren't protected by iCloud Private Relay.
TechCrunch reported that the researchers chose not to report the issue to Apple, with Mysk writing on X that past experience with Apple involved months of delays, inconsistent communication, and in some cases denial of the issue's impact entirely. Apple did not immediately respond to TechCrunch's request for comment.
Macworld notes the issue may require a software update on devices, unlike a previous fix that only required a back-end server change.
The latest report is still under investigation, so it's unclear when or how Apple plans to address it. Mysk and his colleagues develop a private browser called Psylo, which they say now has mitigations that prevent users' IP addresses from leaking when using it.
