Given enough vulnerabilities, anything it wants.
Sorry for being facetious but no one can address as-yet undiscovered zero-days. If user permissions were all that mattered, *nix would have solved security from the get-go.
It's open-source and all, so highly unlikely that it's malicious but if you're concerned, you can try AppArmor. It's seriously annoying but it's for your own good as they say.
Working with AppArmor generally involves:
1. enable in Whonix: https://www.whonix.org/wiki/AppArmor
2. generate profile: (easy) http://www.howtogeek.com/118328/how-to-create-apparmor-profiles-to-lock-down-programs-on-ubuntu
3. spend hours figuring out what all the f*(@&(*@ error messages mean...
Or just let it trash its own dedicated VM and hope that it's not going to attempt a VM breakout. (again, highly unlikely)