Microsoft has confirmed that three new zero-day exploits are being used in ongoing cyberattacks, with 159 vulnerabilities released in this month’s Patch Tuesday round-up. The critical vulnerabilities include eight zero-days, with three already known to be under active exploitation.
The affected vulnerabilities are CVE-2025-21335, CVE-2025-21333, and CVE-2025-21334, which impact Hyper-V, a security feature heavily embedded in modern Windows 11 operating systems. These elevation of privileges issues can allow attackers to gain SYSTEM level permissions on infected devices if they have already gained access through phishing or other attacks.
Microsoft has released an update that protects customers who have installed it. Experts warn that organizations relying on Hyper-V are at risk, with potential impacts including accessing and manipulating virtual machines, stealing sensitive data or credentials, moving laterally within the network, and disrupting critical services.
Cybersecurity experts stress that this month’s Patch Tuesday should be treated as seriously as any other, given the nature of these zero-day exploits. Applying the available security update is recommended, along with strengthening security posture by restricting local access, enforcing strong authentication, and segmenting critical systems.
Source: https://www.forbes.com/sites/daveywinder/2025/01/15/new-critical-microsoft-windows-warning-as-3-zero-day-attacks-underway