VirtualBox/Security and Support Status
VirtualBox has no dedicated maintainer. Whonix VirtualBox support is a leftover from previous times, where no other supported platforms were supported. Images are still being build by Patrick. But Patrick's focus has now moved to Qubes. Grave security issues are unlikely due to Whonix's design. Rudimentary testing of new images and updates is being done by Patrick on a Debian host. There is no Whonix team member testing Whonix in VirtualBox on Windows or Mac hosts. No progress on the VirtualBox development task list should be expected. That's why the supported platforms table lists VirtualBox in the column 'security' with 'testing' for Linux and 'experimental' for Windows and Mac.