Mysk: Apple's Private Relay tool can leak users' IP addresses due to issues in Apple's WebKit browser engine, also affecting OnionBrowser, a Tor browser for iOS
Researchers found a group of issues that mean Private Relay isn't actually protecting users' real IP addresses.
404 MediaJoseph Cox
Context & Ripple Effects
The reported exposure extends a record of WebKit-related privacy and security failures: researchers previously showed that malicious sites could make iOS and macOS WebKit browsers divulge sensitive user data through a WebKit browser attack. Apple has also addressed a wireless identifier exposure that persisted even when a privacy setting was enabled.
Private Relay’s protection is therefore only as reliable as the browser engine handling network activity. The fact that the same issues affect OnionBrowser ties Apple’s WebKit layer to both its own privacy service and an iOS Tor browser.
First-order effects
Private Relay users and OnionBrowser users face potential exposure of their real IP addresses, weakening the privacy outcome those tools are meant to provide.
Apple and OnionBrowser must treat the WebKit issues as a shared browser-engine problem rather than an isolated Private Relay configuration issue.
Second-order effects
Privacy-focused iOS browser developers that depend on WebKit inherit the consequences of fixes and vulnerabilities in Apple’s engine, limiting their ability to independently guarantee network anonymity.
The finding puts greater scrutiny on Apple’s privacy controls after prior cases in which its software bypassed firewalls and VPNs or exposed device identifiers despite enabled protections.
Third-order effects
If WebKit continues to be a common failure point for privacy tools on iOS, browser-engine security becomes a constraint on how credibly third-party apps can differentiate their anonymity protections from Apple’s platform layer.
The pattern shifts privacy assessment from individual branded features toward the interaction of relay services, browser engines, and operating-system networking controls.
The trend: Apple’s privacy products are increasingly being judged on whether protections hold across the shared WebKit and networking layers beneath them.
Soon after we published the blog, we sent a link to the blog and demo website to Apple in a security report to make them aware of it. Now the report is already in the status “We're planning to address the issue you reported.” and a fix is planned for Fall 2026 🤯🤯🤯 [image]
@ProtonVPN VPNs are not affected, since they tunnel the whole device at system level. (mysk) Two other traps. The “dire” quote is Mike Tigas talking about Onion Browser, not Apple. Apple's only on-record line is that it is investigating. (404media) And the test site 404 sent read…
July: Apple's “Hide My Email” leaks real emails. August: Apple's “Private Relay” leaks real user IPs. It's really starting to feel like privacy isn't Apple's strongest suit, despite the billions of dollars sunk into advertising it.
It's only the device's IP address, some DNS requests, and system DNS server IPs that are leaked here. Nothing more. “User data” might imply that more data is exposed, such as the user's email or name. [image]
iCloud Private Relay can leak your IP due to issues with WebKit. This affects all iOS browsers that rely on proxy connections, including Psylo (Apple requires all iOS browsers to use WebKit). We just released Version 1.3.1 to address these issues. More details below👇:
Security Bulletin: WebKit's handling of passkeys can cause iCloud Private Relay to leak your device's real IP address. The same behaviour affects all iOS browsers that rely on proxy connections to hide the device's IP, including Psylo, Onion Browser, and other proxy or Tor [video…
Researchers find a flaw in Apple's Private Relay that exposes users' real IP addresses, which also affects users of Tor's OnionBrowser in iOS: www.404media.co/apples-priva...
New from 404 Media: Apple's ‘Private Relay’ is exposing users' real IP addresses. Private Relay is supposed to protect all your browsing in Safari. But researchers found a bunch of issues that are exposing real IPs. I verified they do. Not fixed, a live issue — www.404media…