The backup implementation in Time Machine in Apple OS X before 10.11 allows local users to obtain access to keychain items via unspecified vectors.
https://support.apple.com/HT205267
http://www.securitytracker.com/id/1033703
http://www.securityfocus.com/bid/76908
http://lists.apple.com/archives/security-announce/2015/Sep/msg00008.html