Missing input validation in system_routes_edit.php
system_routes_edit.php doesn't validate that the gateway selected is the same protocol as the entered "Destination network". Routes to an IPv4 network can't be added to an IPv6 gateway nor vice versa. If an IPv4 gateway is chosen, the "Destination network" must be an IPv4 subnet (including a valid v4 subnet mask, > 32 only valid with v6). If an IPv6 gateway is chosen, the "Destination network" must be an IPv6 subnet.