It has now all been fixed. If your CPU type is still set to KVM64 and you are on epyc7543-3, you can restart your server once and it will be host again.
Posted Apr 25, 2025 - 07:47 CEST
Investigating
A critical security vulnerability has been identified in Proxmox. As a precaution, we are performing urgent upgrades on all affected host systems to ensure infrastructure security and stability.