CVE-2025-21333: 
vulnerability analysis and mitigation

Windows Hyper-V NT Kernel Integration VSP Elevation of Privilege Vulnerability (CVE-2025-21333) is a heap-based buffer overflow vulnerability discovered in January 2025. The vulnerability affects Windows Hyper-V's NT Kernel Integration Virtualization Service Provider (VSP), which manages communication between virtual machines and the host operating system. This vulnerability was discovered by an Anonymous researcher and was confirmed to be exploited in the wild as a zero-day (Tenable Blog, Help Net Security).

The vulnerability has been assigned a CVSSv3 score of 7.8 (High) with the following vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. It is classified as a heap-based buffer overflow vulnerability (CWE-122) that affects the Windows Hyper-V NT Kernel Integration VSP component (NVD).

A successful exploitation of this vulnerability allows an authenticated, local attacker to elevate privileges to SYSTEM level on the compromised Windows and Windows Server machines. This level of access gives attackers complete control over the host system, making it particularly concerning for organizations relying on Hyper-V, including data centers, cloud providers, and enterprise IT environments (Help Net Security).

Microsoft has released patches for this vulnerability as part of the January 2025 Patch Tuesday update. Organizations are advised to apply the security updates as soon as possible to protect their systems (NVD).