TigerVNC, an actively developed open-source VNC server (also for linux), allow the encryption of all the VNC traffic using TLS; this add extra security for the VNC connection without using a SSH tunnel.
To connect to a VNC secured with TLS, the viewer client must support this feature (as the TigerVNC viewer does).
It would be nice if this feature will be available also for the embedded VNC viewer.
You can find more detail about TLS for VNC here:
I will add this to our todo list.