On Juniper Networks products or platforms running Junos OS 11.4 prior to 11.4R13-S3, 12.1X46 prior to 12.1X46-D60, 12.3 prior to 12.3R12-S2 or 12.3R13, 12.3X48 prior to 12.3X48-D40, 13.2X51 prior to 13.2X51-D40, 13.3 prior to 13.3R10, 14.1 prior to 14.1R8, 14.1X53 prior to 14.1X53-D12 or 14.1X53-D35, 14.1X55 prior to 14.1X55-D35, 14.2 prior to 14.2R7, 15.1 prior to 15.1F6 or 15.1R3, 15.1X49 prior to 15.1X49-D60, 15.1X53 prior to 15.1X53-D30 and DHCPv6 enabled, when a crafted DHCPv6 packet is received from a subscriber, jdhcpd daemon crashes and restarts. Repeated crashes of the jdhcpd process may constitute an extended denial of service condition for subscribers attempting to obtain IPv6 addresses.
https://kb.juniper.net/JSA10769