The kernel in Apple iOS before 8.3, Apple OS X before 10.10.3, and Apple TV before 7.2 allows attackers to cause a denial of service (out-of-bounds memory access) or obtain sensitive memory-content information via a crafted app.
http://lists.apple.com/archives/security-announce/2015/Apr/msg00001.html
http://lists.apple.com/archives/security-announce/2015/Apr/msg00002.html
http://lists.apple.com/archives/security-announce/2015/Apr/msg00003.html
https://support.apple.com/HT204659
https://support.apple.com/HT204661
https://support.apple.com/HT204662
https://support.apple.com/kb/HT204870