Download the extension pack for your version of Virtualbox from the Oracle website. Become the root user on your machine and browse to your downloaded files, and install with:
root# VBoxManage extpack uninstall "Oracle VM VirtualBox Extension Pack"
root# VBoxManage extpack install *.vbox-extpack
root# VBoxManage extpack uninstall "Oracle VM VirtualBox Extension Pack"
root# VBoxManage extpack install *.vbox-extpack