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. […]

Microsoft working to fix Exchange Online mailbox quarantine issue

Microsoft is working to resolve an ongoing Exchange Online issue that has been mistakenly quarantining customers’ mailboxes since Sunday. The incident, tracked by Microsoft under EX1436407, began on July 19 and remained unresolved as of the most recent update Wednesday evening. During this time, affected Exchange Online users have been experiencing issues receiving and sending […]