A cybersecurity researcher known as “Nightmare Eclipse” has revealed two zero-day exploits threatening Windows systems: RoguePlanet and GreatXML. RoguePlanet targets Microsoft Defender, allowing attackers to execute privileged actions and gain SYSTEM-level access on Windows machines. It is a local privilege escalation vulnerability that remains effective on fully updated systems. GreatXML claims to bypass BitLocker disk encryption by manipulating the Windows Recovery Environment, potentially granting access to protected files. However, its effectiveness may be overstated, as it might require administrator-level access. Microsoft advises organizations to implement security updates, treat lost or accessible devices as high-risk, enforce stricter policies, and monitor threat intelligence to mitigate exposure to these vulnerabilities.