The log_config_command function in ntp_parser.y in ntpd in NTP before 4.2.7p42 allows remote attackers to cause a denial of service (ntpd crash) via crafted logconfig commands.
https://www-01.ibm.com/support/docview.wss?uid=swg21989542
https://www-01.ibm.com/support/docview.wss?uid=swg21988706
https://www-01.ibm.com/support/docview.wss?uid=swg21986956
https://www-01.ibm.com/support/docview.wss?uid=swg21985122
https://www-01.ibm.com/support/docview.wss?uid=isg3T1024157
https://github.com/ntp-project/ntp/commit/553f2fa65865c31c5e3c48812cfd46176cffdd27
https://bugzilla.redhat.com/show_bug.cgi?id=1254542
http://www.ubuntu.com/usn/USN-2783-1
http://www.securityfocus.com/bid/76475
http://www.oracle.com/technetwork/topics/security/linuxbulletinapr2016-2952096.html
http://www.openwall.com/lists/oss-security/2015/08/25/3
http://www.debian.org/security/2015/dsa-3388
http://rhn.redhat.com/errata/RHSA-2016-2583.html
http://rhn.redhat.com/errata/RHSA-2016-0780.html
http://lists.opensuse.org/opensuse-security-announce/2016-08/msg00042.html
http://lists.opensuse.org/opensuse-security-announce/2016-07/msg00026.html
http://lists.opensuse.org/opensuse-security-announce/2016-05/msg00048.html
http://lists.fedoraproject.org/pipermail/package-announce/2015-October/169167.html
http://lists.fedoraproject.org/pipermail/package-announce/2015-November/170926.html
http://bk1.ntp.org/ntp-dev/?PAGE=patch&REV=4c4fc141LwvcoGp-lLGhkAFp3ZvtrA