Heap-based buffer overflow in chrony before 1.31.1 allows remote authenticated users to cause a denial of service (chronyd crash) or possibly execute arbitrary code by configuring the (1) NTP or (2) cmdmon access with a subnet size that is indivisible by four and an address with a nonzero bit in the subnet remainder.
https://security.gentoo.org/glsa/201507-01
http://www.securityfocus.com/bid/73955
http://www.oracle.com/technetwork/topics/security/linuxbulletinoct2015-2719645.html
http://www.debian.org/security/2015/dsa-3222
http://listengine.tuxfamily.org/chrony.tuxfamily.org/chrony-announce/2015/04/msg00002.html