Disgruntled researcher leaks “BlueHammer” Windows zero-day exploit

A disgruntled researcher published a public proof-of-concept called "BlueHammer" for an unpatched Windows local privilege escalation (LPE) zero-day that combines a TOCTOU and path confusion to access the Security Account Manager (SAM) and escalate to SYSTEM. The exploit code was posted on GitHub, is reportedly buggy but has been confirmed to work in at least some cases by researchers, and Microsoft had not released a patch at time of reporting.