An issue was discovered in certain Apple products. iOS before 11 is affected. macOS before 10.13 is affected. tvOS before 11 is affected. watchOS before 4 is affected. The issue involves the "Kernel" component. It allows attackers to obtain sensitive network-activity information about arbitrary apps via a crafted app.
https://support.apple.com/HT208144
https://support.apple.com/HT208115