flowd in Juniper Junos 10.4 before 10.4S14, 11.2 and 11.4 before 11.4R6-S2, and 12.1 before 12.1R6 on SRX devices, when certain Application Layer Gateways (ALGs) are enabled, allows remote attackers to cause a denial of service (daemon crash) via crafted TCP packets, aka PRs 727980, 806269, and 835593.

The kernel in Juniper Junos 10.4 before 10.4R14, 11.4 before 11.4R8, 11.4X27 before 11.4X27.43, 12.1 before 12.1R6, 12.1X44 before 12.1X44-D20, 12.2 before 12.2R4, and 12.3 before 12.3R2, in certain VLAN configurations with unrestricted arp-resp and proxy-arp settings, allows remote attackers to cause a denial of service (device crash) via a crafted ARP request, aka PR 842091.

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.

flowd in Juniper Junos 10.4 before 10.4S14, 11.4 before 11.4R8, 12.1 before 12.1R7, and 12.1X44 before 12.1X44-D15 on SRX devices, when PIM and NAT are enabled, allows remote attackers to cause a denial of service (daemon crash) via crafted PIM packets, aka PR 842253.

Memory leak in Juniper JUNOS Packet Forwarding Engine (PFE) allows remote attackers to cause a denial of service (memory exhaustion and device reboot) via certain IPv6 packets.

TCP, when using a large Window Size, makes it easier for remote attackers to guess sequence numbers and cause a denial of service (connection loss) to persistent TCP connections by repeatedly injecting a TCP RST packet, especially in protocols that use long-lived connections, such as BGP.