If your system is using EFI Secure Boot you may need to sign the kernel modules (vboxdrv, vboxnetflt, vboxnetadp, vboxpci) before you can load them.

C++
    sudo -i
    cd /root/module-signing
    chmod 700 /root/module-signing/sign-vbox-modules
    ./sign-vbox-modules

Source

Also in C++: