A mail header parsing issue was addressed with improved checks. This issue is fixed in iOS 18.7.2 and iPadOS 18.7.2, iOS 26.1 and iPadOS 26.1, macOS Sequoia 15.7.2, macOS Sonoma 14.8.2, macOS Tahoe 26.1, visionOS 26.1, watchOS 26.1. An attacker may be able to cause a persistent denial-of-service.
https://support.apple.com/en-us/125639
https://support.apple.com/en-us/125638
https://support.apple.com/en-us/125636
https://support.apple.com/en-us/125635
https://support.apple.com/en-us/125634