No not really, in such a setup it would have no internet access even. Most soho router have no way to set a gateway on the lan.
So even if you forwarded traffic to it from the internet, it wouldn't be able to answer back, unless you also had setup a source nat on pfsense.
While sure as any device on your network, pc, iot device, etc. It's on your network and things on your network would be able to talk to it.. But not sure what sort of vulnerability you would be worried about in such a setup.
Correctly secure your wifi, wpa2 with good complex length psk and you should be good to go.