It was discovered that ntpq and ntpdc disclosed the origin timestamp to unauthenticated clients, which could permit such clients to forge the server"s replies. The process_packet function in ntp_proto.c in ntpd in NTP 4.x before 4.2.8p8 allows remote attackers to cause a denial of service by sending spoofed packets from many source IP addresses in a certain scenario, as demonstrated by triggering an incorrect leap indication. ntpd in NTP 4.x before 4.2.8p8, when autokey is enabled, allows remote attackers to cause a denial of service by sending a spoofed crypto-NAK packet or a packet with an incorrect MAC value at a certain time. ntpd in NTP 4.x before 4.2.8p8 allows remote attackers to cause a denial of service via a spoofed broadcast packet. This vulnerability exists because of an incomplete fix for CVE-2016-1548