1. Executive summary GreatXML is a public proof-of-concept, released on 10 June 2026 by the researcher Nightmare Eclipse / Chaotic Eclipse / MSNightmare, claiming a BitLocker bypass. The technique abuses the Windows Recovery Environment (WinRE), the state left behind by Microsoft Defender’s Offline Scan feature, and the legitimate processing of unattended setup answer files (unattend.xml).…
