Juniper Junos 11.4 before 11.4R8 12.1X44 before 12.1X44-D35 12.1X45 before 12.1X45-D25 12.1X46 before 12.1X46-D20 12.1X47 before 12.1X47-D10 12.2 before 12.2R9 12.3R2 before 12.3R2-S3 12.3 before 12.3R3 13.1 before 13.1R4 and 13.2 before 13.2R1 allows remote attackers to cause a denial of service (assertion failure and rpd restart) via a crafted BGP FlowSpec prefix.