Kerio Personal Firewall (KPF) 2.1.4 has a default rule to accept incoming packets from DNS (UDP port 53), which allows remote attackers to bypass the firewall filters via packets with a source port of 53.
Kerio Personal Firewall (KPF) 2.1.4 and earlier allows remote attackers to cause a denial of service (hang and CPU consumption) via a SYN packet flood.