Confirmed here. After updating kernel-default from 5.12.12-1.1 to 5.13.0-1.1 and virtualbox-kmp-default from 6.1.22_k5.12.12_1-3.6 to 6.1.22_k5.13.0_1-3.8 VirtualBox crashes when trying to start a Windows 10 guest on Tumbleweed. VBox.log attached.