Buffer overflow in flowd in Juniper Junos 10.4 before 10.4S14, 11.4 before 11.4R7, 12.1 before 12.1R6, and 12.1X44 before 12.1X44-D15 on SRX devices, when Captive Portal is enabled with the UAC enforcer role, allows remote attackers to execute arbitrary code via crafted HTTP requests, aka PR 849100.