A bug in iOS 16 reportedly causes the Mail application on iPhone and iPad models updated to the latest version of Apple’s operating system to crash, rendering it inaccessible. The bug comes in the form of an otherwise routine-looking email message, which has an unusual sender field containing extra characters causing the Mail application to crash on iOS 16. The bug has been dubbed “Mailjack” and allows any outsider to lock down iPhone and iPad users out of their email accounts with a modified email.
The crash-triggering email was identified by Equinux’s VPN Tracker. In general, the “From” field has the sender’s name followed by their email address in syntax — From: [email protected] However, the email that caused the crash had the syntax of the field from as — From: “”@example.com. Mail services such as Gmail, Outlook, and Hotmail automatically rewrite such incoming emails using unusual syntax to avoid such triggers.
While Gmail and Yahoo have filters to block these maliciously crafted emails altogether, Apple’s first-party iCloud Mail does not appear to have such rewrite or filtering mechanisms, according to the report.
The current solution to avoid the trigger is to delete the message from the inbox or spam folder on a device with an older iOS version or via a third-party email client. Users can also choose to move the trigger email to another subfolder on an IMAP email account. However, if you navigate to the respective subfolder, the application will crash again according to the website. Administrators can also choose to add the syntax “”@example.com to their list of blocked emails via email security software or firewall.
Equinux’s VPN Tracker has created a special webpage where users can test the bug trigger by entering their email address. However, users are advised not to try this as it could lock them out of their emails unless they have access to an older iOS or third-party email client to remove the trigger message.