Microsoft issued an emergency out-of-band update to address the so-called PrintNightmare vulnerability for Windows 10 version 1607, Windows Server 2012, and Windows Server 2016. The fix for the remote execution exploit in the Windows Print Spooler service can be bypassed in certain scenarios, allowing attackers to run arbitrary code on infected systems. The main concern with the threat is that non-administrator users had the ability to load their own printer drivers on a print server. Microsoft: “Administrator users who are not administrators can only install signed print drivers”
Source: https://thehackernews.com/2021/07/microsofts-emergency-patch-fails-to.html