The issue is related to the processing of font files, which may lead to arbitrary code execution. Apple is aware of a report that this issue may have been actively exploited against versions of iOS released before iOS 15.7.1. The vulnerability is associated with a buffer overflow in the FontParser component of Apple's operating systems. It is estimated that a large number of devices may be affected, but the exact number is not specified. The issue was addressed with improved handling of caches.