Apple's 'Private Relay' Is Exposing Users' Real IP Addresses

iCloud Private Relay routes web traffic through Apple-controlled relays to mask the client’s IP address, but researchers discovered a scenario where that masking fails. The failure occurs when a device processes a passkey request, which is part of the WebAuthn standard for password-less login. In that flow, the request originates from the operating system rather than the Safari browser, so it never traverses the relay path. The result is that the destination server sees the user’s true IP address despite the relay being enabled.

The technical root is the OS credential service issuing a fetch operation independently of the browser’s networking stack. Because Private Relay only proxies traffic that passes through Safari, any OS-level request bypasses the relay entirely. This design choice means that the privacy layer is not applied uniformly across all network activity on the device. Consequently, the exposure is not limited to a specific website but applies to any service that triggers a passkey request.

For engineers building web services that support passkeys, the leak changes the threat model: the client’s IP can no longer be assumed hidden by Private Relay. Logging or geolocation based on IP will now reflect the user’s real network location, which may affect analytics, fraud detection, or compliance requirements. Developers of privacy-focused applications must recognize that enabling passkeys may unintentionally reveal user identifiers they intended to protect.

Apple has been notified of the issue and acknowledges its seriousness, but no remediation timeline has been provided. Until a fix is deployed, the vulnerability remains present in the current OS release. Engineers cannot rely on Private Relay to provide IP masking for passkey flows and should consider alternative mitigations, such as server-side handling that does not depend on client IP anonymity.

Practical steps include testing applications with the researchers’ verification site to confirm whether the leak occurs for your user base, and informing users of the limitation when they enable passkeys. If IP privacy is critical, consider advising users to disable passkey usage or to employ browsers that enforce proxying for all network calls. Monitoring Apple’s security updates for a patch will be essential to restore the intended privacy guarantees.