Microsoft have released KB5004945 emergency security update to fix the actively exploited PrintNightmare vulnerability in the Windows Print Spooler service impacting all Windows versions. Microsoft has not yet issued patches for all versions of Windows but they will be coming soon.
The Microsoft Security Response Center reports that a remote code execution vulnerability exists when the Windows Print Spooler service improperly performs privileged file operations. An attacker who successfully exploited this vulnerability could run arbitrary code with SYSTEM privileges. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.