An issue was discovered in certain Apple products. iOS before 11.2.5 is affected. macOS before 10.13.3 is affected. tvOS before 11.2.5 is affected. watchOS before 4.2.2 is affected. The issue involves the "QuartzCore" component. It allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption and application crash) via a crafted web site.
https://support.apple.com/HT208465
https://support.apple.com/HT208464
https://support.apple.com/HT208463
https://support.apple.com/HT208462
http://www.securitytracker.com/id/1040267