On Juniper Networks MX Series with MS-MIC or MS-MPC card configured with NAT64 configuration, receipt of a malformed IPv6 packet may crash the MS-PIC component on MS-MIC or MS-MPC. This issue occurs when a multiservice card is translating the malformed IPv6 packet to IPv4 packet. An unauthenticated attacker can continuously send crafted IPv6 packets through the device causing repetitive MS-PIC process crashes, resulting in an extended Denial of Service condition. This issue affects Juniper Networks Junos OS on MX Series: 15.1 versions prior to 15.1R7-S7; 15.1X53 versions prior to 15.1X53-D593; 16.1 versions prior to 16.1R7-S8; 17.2 versions prior to 17.2R3-S4; 17.3 versions prior to 17.3R3-S6; 17.4 versions prior to 17.4R2-S11, 17.4R3; 18.1 versions prior to 18.1R3-S11; 18.2 versions prior to 18.2R3-S6; 18.2X75 versions prior to 18.2X75-D41, 18.2X75-D430, 18.2X75-D53, 18.2X75-D65; 18.3 versions prior to 18.3R2-S4, 18.3R3; 18.4 versions prior to 18.4R2-S5, 18.4R3; 19.1 versions prior t…