CYBER-CRIME
Exploit Wednesday's back, baby
Nightmare Eclipse, the serial zero-day hunter who has an axe to grind with Microsoft, published a new Defender zero-day, ShieldBreak, that apparently bypasses Redmond’s RoguePlanet patch (CVE-2026-50656), allowing attackers to gain SYSTEM privileges on fully patched Windows 10, Windows 11, and Windows Server systems.According to at least one other researcher, the exploit works. “I've tried it, it works on latest Windows 11,” former Microsoft employee and security expert Kevin Beaumont said. Beaumont also published three detections and hunting queries for ShieldBreak to help defenders rapidly find any stealthy threats. So until Microsoft fixes this latest zero-day, we’d highly suggest using these queries.ShieldBreak is the 10th zero-day from Nightmare Eclipse since they began their scorched-earth strategy against Microsoft in early April. The prolific bug finder and exploit developer is suspected to be a former, very disgruntled, Microsoft employee. And in typical fashion, this latest zero-day drop occurred just hours after Redmond’s monthly Patch Tuesday that fixed 421 security problems in its products - but ShieldBreak isn't one of them.
It’s a local privilege-escalation exploit that, according to Nightmare, allows attackers to gain SYSTEM-level privileges.
