Siri in Apple iOS before 9.2 allows physically proximate attackers to bypass an intended client-side protection mechanism and obtain sensitive content-notification information by listening to a device in the lock-screen state.
https://support.apple.com/HT205635
http://www.securitytracker.com/id/1034348
http://lists.apple.com/archives/security-announce/2015/Dec/msg00000.html