Microsoft Defender
Microsoft working on Defender patch for ShieldBreak zero-day
On Friday, Microsoft confirmed it has begun working on a security patch for a Defender zero-day vulnerability named “ShieldBreak.” A security researcher who uses the “Nightmare Eclipse” handle disclosed this privilege escalation vulnerability after Microsoft released the August 2026 Patch Tuesday security updates. ”Microsoft is aware of the reported vulnerability and is actively investigating the […]
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 Kevin […]
Microsoft patches RoguePlanet Defender zero-day vulnerability
Microsoft has released a security patch to address a Defender zero-day vulnerability known as “RoguePlanet,” disclosed after the June 2026 Patch Tuesday. The flaw (tracked as CVE-2026-50656) was disclosed by a security researcher using the “Nightmare Eclipse” handle as part of an ongoing dispute with Microsoft over the company’s bug bounty and vulnerability disclosure practices. They […]
Microsoft working on Defender patch for RoguePlanet zero-day
Microsoft confirmed that it’s working on a security patch for a Defender zero-day vulnerability named “RoguePlanet,” disclosed one week ago. The security researcher who published a RoguePlanet exploit during the June 2026 Patch Tuesday (known as Nightmare Eclipse) said it affects fully patched Windows 10 and Windows 11 devices and allows attackers to spawn command prompts with […]
Microsoft Defender ‘RoguePlanet’ zero-day grants SYSTEM privileges
A security researcher has released a new Microsoft Defender zero-day exploit named “RoguePlanet” just hours after Microsoft fixed two previously disclosed flaws during June 2026 Patch Tuesday. The researcher, known as Nightmare Eclipse, says the new vulnerability affects fully patched Windows 10 and Windows 11 devices, allowing attackers to spawn a command prompt with SYSTEM privileges via […]
Microsoft Defender can now automatically isolate hacked endpoints
Microsoft is testing a new Defender for Endpoint capability that will automatically isolate compromised endpoints to thwart attackers’ attempts to move laterally across the network. This is now available in preview mode and works as part of automatic attack disruption, a feature designed to contain attacks, limit their impact, and provide security teams with more remediation time. […]
Microsoft warns of new Defender zero-days exploited in attacks
On Wednesday, Microsoft started rolling out security patches for two Defender vulnerabilities that have been exploited in zero-day attacks. The first one, tracked as CVE-2026-41091, is a privilege escalation security flaw affecting Microsoft Malware Protection Engine 1.1.26030.3008 and earlier, which provides the scanning, detection, and cleaning capabilities for Microsoft antivirus and antispyware software. This flaw stems […]
Microsoft Defender wrongly flags DigiCert certs as Trojan:Win32/Cerdigent.A!dha
Microsoft Defender is detecting legitimate DigiCert root certificates as Trojan:Win32/Cerdigent.A!dha, resulting in widespread false-positive alerts, and in some cases, removing certificates from Windows. According to cybersecurity expert Florian Roth, the issue first appeared after Microsoft added the detections to a Defender signature update on April 30th. Today, administrators worldwide began reporting that DigiCert root certificate entries were flagged as malware and, on […]
CISA orders feds to patch BlueHammer flaw exploited as zero-day
CISA has given U.S. government agencies two weeks to secure their Windows systems against a Microsoft Defender privilege escalation vulnerability that has been exploited in zero-day attacks. Tracked as CVE-2026-33825, this high-severity security flaw allows low-privileged local threat actors to gain SYSTEM permissions on unpatched devices by exploiting an insufficient granularity of access control weakness. Microsoft patched […]
New Microsoft Defender “RedSun” zero-day PoC grants SYSTEM privileges
A researcher known as “Chaotic Eclipse” has published a proof-of-concept exploit for a second Microsoft Defender zero-day, dubbed “RedSun,” in the past two weeks, protesting how the company works with cybersecurity researchers. This exploit is for a local privilege escalation (LPE) flaw that grants SYSTEM privileges in Windows 10, Windows 11, and Windows Server on […]