An issue was discovered in certain Apple products. iOS before 11.4 is affected. macOS before 10.13.5 is affected. tvOS before 11.4 is affected. watchOS before 4.3.1 is affected. The issue involves the "libxpc" component. It allows attackers to gain privileges via a crafted app that leverages a logic error.
https://www.exploit-db.com/exploits/45916/
https://support.apple.com/HT208851
https://support.apple.com/HT208850
https://support.apple.com/HT208849