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 "Carbon" component. It allows remote attackers to execute arbitrary code or cause a denial of service (buffer overflow and application crash) via a crafted .dfont file.
https://support.apple.com/HT207617
https://support.apple.com/HT207615
https://support.apple.com/HT207602
https://support.apple.com/HT207601