The mx4200_send function in the legacy MX4200 refclock in NTP before 4.2.8p10 and 4.3.x before 4.3.94 does not properly handle the return value of the snprintf function, which allows local users to execute arbitrary code via unspecified vectors, which trigger an out-of-bounds memory write.
https://support.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbux03962en_us
https://support.apple.com/HT208144
http://www.securitytracker.com/id/1039427
http://www.securitytracker.com/id/1038123
http://www.securityfocus.com/bid/97058
http://support.ntp.org/bin/view/Main/SecurityNotice#March_2017_ntp_4_2_8p10_NTP_Secu