An issue was discovered in certain Apple products. iOS before 11.2.6 is affected. macOS before 10.13.3 Supplemental Update is affected. tvOS before 11.2.6 is affected. watchOS before 4.2.3 is affected. The issue involves the "CoreText" component. It allows remote attackers to cause a denial of service (memory corruption and system crash) or possibly have unspecified other impact via a crafted string containing a certain Telugu character.