An issue was discovered in certain Apple products. iOS before 10.3 is affected. macOS before 10.12.4 is affected. tvOS before 10.2 is affected. watchOS before 3.2 is affected. The issue involves the "CoreText" component. It allows remote attackers to cause a denial of service (resource consumption) via a crafted text message.
https://support.apple.com/HT207617
https://support.apple.com/HT207615
https://support.apple.com/HT207602
https://support.apple.com/HT207601