The Apple Pay component in Apple iOS before 9 allows remote terminals to obtain sensitive recent-transaction information during payments by leveraging the transaction-log feature.
http://lists.apple.com/archives/security-announce/2015/Oct/msg00003.html
http://lists.apple.com/archives/security-announce/2015/Sep/msg00001.html
http://lists.apple.com/archives/security-announce/2015/Sep/msg00005.html
https://support.apple.com/HT205212
https://support.apple.com/HT205213