Microsoft has provided mitigation guidance to block attacks on systems vulnerable to exploits targeting the Windows Print Spooler zero-day vulnerability known as PrintNightmare. Remote code execution (RCE) bug now tracked as CVE-2021-34527 impacts all versions of Windows per Microsoft, with the company still investigating if the vulnerability is exploitable on all of them. Microsoft didn’t share who is behind the detected exploitation (threat actors or security researchers) CISA has also issued a notification on the bug encouraging admins to disable the Windows print spooler service on servers not used for printing.
Source: https://www.bleepingcomputer.com/news/security/microsoft-shares-mitigations-for-windows-printnightmare-zero-day-bug/