ntp is vulnerable to denial of service. It was found that when NTP was configured in broadcast mode, a remote attacker could broadcast packets with bad authentication to all clients. The clients, upon receiving the malformed packets, would break the association with the broadcast server, causing them to become out of sync over a longer period of time.
lists.fedoraproject.org/pipermail/package-announce/2016-February/177507.html
lists.fedoraproject.org/pipermail/package-announce/2016-January/176434.html
lists.opensuse.org/opensuse-security-announce/2016-04/msg00059.html
lists.opensuse.org/opensuse-security-announce/2016-04/msg00060.html
lists.opensuse.org/opensuse-security-announce/2016-05/msg00020.html
lists.opensuse.org/opensuse-security-announce/2016-05/msg00038.html
lists.opensuse.org/opensuse-security-announce/2016-05/msg00048.html
lists.opensuse.org/opensuse-security-announce/2016-07/msg00026.html
lists.opensuse.org/opensuse-security-announce/2016-08/msg00042.html
lists.opensuse.org/opensuse-updates/2016-05/msg00114.html
rhn.redhat.com/errata/RHSA-2016-1552.html
rhn.redhat.com/errata/RHSA-2016-2583.html
support.ntp.org/bin/view/Main/SecurityNotice#April_2016_NTP_4_2_8p7_Security
tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20160127-ntpd
www.debian.org/security/2016/dsa-3629
www.oracle.com/technetwork/topics/security/linuxbulletinapr2016-2952096.html
www.securityfocus.com/bid/81816
www.securitytracker.com/id/1034782
www.ubuntu.com/usn/USN-3096-1
access.redhat.com/errata/RHSA-2016:1141
access.redhat.com/security/updates/classification/#moderate
bto.bluecoat.com/security-advisory/sa113
cert-portal.siemens.com/productcert/pdf/ssa-497656.pdf
h20566.www2.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbhf03750en_us
h20566.www2.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbhf03766en_us
security.FreeBSD.org/advisories/FreeBSD-SA-16:09.ntp.asc
security.gentoo.org/glsa/201607-15
security.netapp.com/advisory/ntap-20171031-0001/
us-cert.cisa.gov/ics/advisories/icsa-21-103-11
www.kb.cert.org/vuls/id/718152