These updates are not delivered through Windows Updates and will not install automatically on impacted servers. To get the standalone package, admins must search for the KB number in the Microsoft Update Catalog, download it, and install it manually. They can also be manually imported into Windows Server Update Services (WSUS) and Microsoft Endpoint Configuration Manager. Microsoft also provides instructions on importing updates into WSUS and Configuration Manager from the Microsoft Update Catalog. “You do not need to apply any previous update before installing these cumulative updates,” Redmond added. “If you have already installed updates released December 13, 2022, you do not need to uninstall the affected updates before installing any later updates, including the updates listed above.” A temporary fix is also available for admins who cannot immediately install the updates on affected SDN-based SCVMM deployments. This workaround requires running a set of commands on all SCVMM-managed Hyper-V hosts from an elevated PowerShell window (immediately after installing the KB5021237 and KB5021249 updates). Administrators can find scripts for large-scale deployments on the SCVMM Management Server and further details on applying the workaround on the Microsoft support site.
https://www.bleepingcomputer.com/news/microsoft/microsoft-pushes-emergency-fix-for-windows-server-hyper-v-vm-issues/
