CVE-2025-21335 is a use-after-free vulnerability (CWE-416) in the Windows Hyper-V NT Kernel Integration VSP on Windows 10 Version 21H2 (build 10.0.19044.0). The vulnerability allows elevation of privilege due to improper handling of kernel objects, enabling an attacker with local access and low privileges to gain higher privileges. The CVSS 3.1 base score is 7.8, indicating high severity. Microsoft has released an official fix for this vulnerability as documented in their security update guide.

Successful exploitation of this vulnerability could allow an attacker with limited privileges on a Windows 10 Version 21H2 system to elevate their privileges to a higher level, potentially leading to full system compromise. The vulnerability affects confidentiality, integrity, and availability with high impact ratings. There are no known exploits in the wild at the time of publication.

An official fix is available from Microsoft. It is recommended to apply the security update provided by Microsoft for Windows 10 Version 21H2 (build 10.0.19044.0) as soon as possible to remediate this vulnerability. Refer to the Microsoft advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-21335 for update details and installation instructions.