Security researcher Nightmare Eclipse released the ShieldBreak zero-day exploit for Microsoft Windows on August 12, 2026.
The exploit grants attackers maximum system privileges on fully patched Windows 10, Windows 11, and Windows Server systems. This release occurred immediately following Microsoft’s August Patch Tuesday security updates.
ShieldBreak functions as a bypass for RoguePlanet, a vulnerability Microsoft previously patched. The disclosure stems from a public dispute over Microsoft’s bug bounty program and disclosure policies.
Microsoft previously threatened the researcher with legal action for disclosing vulnerabilities without coordination.