Apple Safari before 6.2.8, 7.x before 7.1.8, and 8.x before 8.0.8, as used in iOS before 8.4.1 and other products, does not indicate what web site originated an input prompt, which allows remote attackers to conduct spoofing attacks via a crafted site.
http://lists.apple.com/archives/security-announce/2015/Aug/msg00000.html
http://lists.apple.com/archives/security-announce/2015/Aug/msg00002.html
https://support.apple.com/kb/HT205030