I don't know so much about it, but it sounds like even stuff running in VMs isn't safe from this, if you are browsing the web on a VM then this exploit could affect the host. Be careful out there.
Discussion
Sure, but it would be limited to that one VM
On any given day I run 3-7 or more all in the one GUI that is the core function of QubesOS, so anything with risk goes into a separate one :-)