The getresponse function in ntpq in NTP versions before 4.2.8p9 and 4.3.x before 4.3.90 allows remote attackers to cause a denial of service (infinite loop) via crafted packets with incorrect values.
http://rhn.redhat.com/errata/RHSA-2016-2583.html
https://h20566.www2.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbhf03750en_us
https://h20566.www2.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbhf03766en_us
https://security.FreeBSD.org/advisories/FreeBSD-SA-16:09.ntp.asc
https://security.gentoo.org/glsa/201607-15
https://security.netapp.com/advisory/ntap-20171031-0001/
https://www.kb.cert.org/vuls/id/718152