The current version of Virtualbox for Kali Linux 2018.4 is the latest verion 5.2.22. Since the official version of Virtualbox cannot be installed on Kali Linux, the Kali version is to be installed. Luckily, it is the latest version.
apt update
apt install virtualbox-dkms virtualbox-ext-pack virtualbox-guest-additions-iso
That's all! See you.