Information security
fromSecurityWeek
1 week agoRecent Microsoft Defender Vulnerability Exploited as Zero-Day
A zero-day vulnerability in Microsoft Defender, tracked as CVE-2026-33825, allows privilege escalation through a flaw named BlueHammer.
In a service alert spotted by BleepingComputer, Microsoft revealed that the glitch started on February 5 and has been preventing some Exchange Online users from sending and receiving emails. "Some users' legitimate email messages are being marked as phish and quarantined in Exchange Online," Microsoft said in the service alert. "We've determined that the URLs associated with these email messages are incorrectly marked as phish and quarantined in Exchange Online due to ever-evolving criteria aimed at identifying suspicious email messages, as spam and phishing techniques have become more sophisticated in avoiding detection."
Microsoft Defender is the built-in anti-malware package that's included with modern Windows operating systems. It's alternatively known as Windows Security (it shows up under Settings > Privacy & security as Windows Security), Windows Defender, or Microsoft Defender Antivirus, as on this Microsoft Learn page. But whatever you want to call it, for many Windows users, this tool is the go-to default for handling security on their PCs.
You probably know by now that 10-year-old Windows 10 is no longer supported. Microsoft won't provide bug fixes, security patches, or other important updates to defend these PCs against new vulnerabilities. However, if you're still running Windows 10, the good news is Microsoft Defender will still protect your computer against viruses and other threats. Protected by Defender In a Tuesday blog post spotted by the folks at Neowin, Microsoft explained how Defender in its different incarnations will continue to work as expected in Windows 10.