I replied to James who is on 5.3 not 5.13. I am on 5.13 with same problem and I can confirm. We need to wait for a virtualbox update to support 5.13 kernel.

On Sat, Jul 10, 2021 at 9:51 PM Winfried Bartnick <winni@bartnick.info> wrote:

No, I am on Tumbleweed and I am not the only one with this problem.
Am 10.07.21 um 20:19 schrieb Stratos Zolotas:

On Sat, Jul 10, 2021 at 7:57 PM James Knott <james.knott@jknott.net> wrote:

I have kernel-default-5.3.18-59.10.1.x86_64 and it runs VirtualBox
without problem.

You have 5.3 not 5.13. You are on leap 15.2 not tumbleweed.