I haven't updated VBOX in ages but have never seen this issue and it has my CPU running at 100C.
Manually/forcefully killing the process does not work with "kill -kill 3892".
I've closed the VBOXManager and everything else related to it.
This did seem to happen around the time I ran VBoxManage clonehd and it failed, the terminal issue locked up and also never wrote a byte of anything. I forced killed the VBoxManage and tried to remove "rm" the empty image and that "rm" process is still locked and can't be force killed.