https://www.bleepingcomputer.com/news/microsoft/zero-day-bug-in-all-windows-versions-gets-free-unofficial-patch/

A free and unofficial patch is now available for a zero-day local privilege escalation vulnerability in the Windows User Profile Service that lets attackers gain SYSTEM privileges under certain conditions.

The bug, tracked as CVE-2021-34484, was incompletely patched by Microsoft during the August Patch Tuesday. The company only addressed the impact of the proof-of-concept (PoC) provided by security researcher Abdelhamid Naceri who reported the issue.