An out-of-bounds write was addressed with improved input validation. This issue is fixed in iOS 14.5 and iPadOS 14.5, watchOS 7.4, Security Update 2021-003 Catalina, tvOS 14.5, macOS Big Sur 11.3. Processing a maliciously crafted image may lead to arbitrary code execution.
https://support.apple.com/en-us/HT212530
https://support.apple.com/en-us/HT212325
https://support.apple.com/en-us/HT212324