Microsoft patches LegacyHive Windows zero-day vulnerability

Microsoft has released security patches to address a Windows zero-day vulnerability known as “LegacyHive,” disclosed after the July 2026 Patch Tuesday. The security flaw was disclosed by a security researcher who uses the “Nightmare Eclipse” handle in protest of Microsoft’s bug bounty and vulnerability disclosure practices. Nightmare Eclipse published a LegacyHive proof-of-concept (PoC) exploit hours […]

Hackers leverage new Microsoft SharePoint exploit in attacks

A proof-of-concept (PoC) exploit for a critical Microsoft SharePoint vulnerability, published by cybersecurity company Rapid7 on Tuesday, is already being used in attacks. Tracked as CVE-2026-55040, this authentication bypass security flaw in the JWT token validation pipeline can be exploited by attackers without privileges to perform operations as a SharePoint site user or administrator. Microsoft […]

New Microsoft Defender ‘ShieldBreak’ zero-day grants SYSTEM privileges

A security researcher known as Nightmare Eclipse has released a new Microsoft Defender zero-day exploit named “ShieldBreak” after Microsoft released the August 2026 Patch Tuesday security updates. The new vulnerability is described as a bypass for RoguePlanet, another Defender privilege escalation flaw disclosed in June and patched by Microsoft one month later. However, cybersecurity expert […]

CISA: Microsoft SharePoint flaw now exploited in ransomware attacks

CISA confirmed today that ransomware gangs have begun abusing a high-severity Microsoft SharePoint remote code execution vulnerability, which has been flagged as actively exploited since early July. Tracked as CVE-2026-45659, this security flaw stems from a deserialization of untrusted data weakness and allows attackers with low privileges to execute arbitrary code on unpatched SharePoint servers. […]