Chaotic Eclipse Unveils LegacyHive Exploit Affecting Fully Patched Windows Systems
LegacyHive PoC exposes a Windows Privilege Escalation flaw affecting fully patched Windows desktop and server systems. Just hours after Microsoft’s July 2026 Patch Tuesday, security researcher Nightmare Eclipse, also known as Chaotic Eclipse, published a new Windows zero-day proof-of-concept called LegacyHive. This time, the target is the Windows User Profile Service (ProfSvc), and unlike the […]

Just hours after Microsoft’s July 2026 Patch Tuesday, security researcher Nightmare Eclipse, also known as Chaotic Eclipse, published a new Windows zero-day proof-of-concept called LegacyHive. This time, the target is the Windows User Profile Service (ProfSvc), and unlike the hundreds of vulnerabilities Microsoft fixed this month, this one currently has no CVE, no advisory, and no security update.
LegacyHive is a local privilege escalation vulnerability. An attacker who already has code execution as a standard user can abuse the User Profile Service to load another user’s registry hive, potentially that of a local administrator, under their own profile.
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