In todays world almost any device that attaches to the network (Computers, Tablets, Game Systems, TVs, Vera, Cable Boxes, DVD players, Stereo Tuners, Media Players, Cameras, Printers, .... ) all can be used as base for an exploit on your LAN.
The pragmatic way to deal with security is to:
1) Secure your Network ... NO incoming connections except maybe a VPN
2) Trust the devices you install on the network.
By design/conformance to industry standards (UPNP) Vera can NOT secure all of it's protocols. So anyone that has LAN access has access to the Devices connected to Vera ... even if you secure the Browser Connection.
If that does not work for you I suggest a different (Non Vera) solution.
Also any device you can download programs (Like Vera downloading Plugins) also opens up a potential source of malware. Most of the GOOD software on Vera comes from 3rd party developers ... any one of us could use Vera to exploit your LAN.
The question is who, what, and how much do you Trust ?