iOS 16 Mail app crashes with this sender email format

A specifically formatted email address can cause the iOS 16 Mail app to stop working for users. The app continues to crash when opening. This bug impacts not just the final release of iOS 16 and iPadOS 16, but also iOS 16.1 beta and iPadOS 16.1 beta.

iOS 16 Mail app bug

Mail app crash bug with iOS 16

The bug only works with email services like iCloud, and other IMAP email services that do not correct or rewrite inbound mails. Popular email services like Gmail, Yahoo, and Outlook rewrite inbound mails and block such malicious sender email addresses.

The bug has been discovered by VPN Tracker, after reports from their team members about the Mail app crashing upon launch. All the team members who reported the issue had received the same spam email. Upon investigation, it turned out that the sender’s email address was causing the issue.

Standard email addresses are formatted as following;

sender@example.com

However, the spam email address had the following format:

""@example.com

The “” in the email is what causes the issue, and forces the Mail app in iOS 16 and iPadOS 16 to crash. This bug basically locks out users from their Mail app, as long as they are using iCloud Mail or any IMAP email service that does not detect and block this format of email addresses.

VPN Tracker are calling this issue Mailjack. It allows anyone to lock the receiver’s Mail app on iOS 16. The only solution is to access email using a browser or desktop email client, and delete the malicious mail message from the inbox or spam. Once the Mail app syncs again, the bug should resolve itself.

The company has created a form to test this issue. Users can enter their iCloud email address and will receive an email with the maliciously formatted sender address. We don’t recommend that you test it on your device, since the issue is proven to work. However, if you want to test whether your non-iCloud IMAP email service is effected by this issue, the form can prove to be helpful. 

VPN Tracker have filed the bug with Apple’s Security team so hopefully, the bug will be fixed in an upcoming iOS update.

Apple has a bunch of bugs to fix with iOS 16 and iPhone 14 Pro, and a software update is expected soon. It’s yet to be seen whether Apple will include a fix for this Mail app issue too.

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