MapKit in Apple iOS before 9.3.2, OS X before 10.11.5, and watchOS before 2.2.1 does not use HTTPS for shared links, which allows remote attackers to obtain sensitive information by sniffing the network for HTTP traffic.
lists.apple.com/archives/security-announce/2016/May/msg00002.html
lists.apple.com/archives/security-announce/2016/May/msg00003.html
lists.apple.com/archives/security-announce/2016/May/msg00004.html
www.securitytracker.com/id/1035890
support.apple.com/HT206566
support.apple.com/HT206567
support.apple.com/HT206568