CVE-2025-21333: Microsoft Windows Hyper-V NT Kernel Integration VSP Heap-based Buffer Overflow Vulnerability

Vulnerability summary

CVE-2025-21333 is a high (CVSS 7.8) Heap-based Buffer Overflow vulnerability in Microsoft Windows. It is known to be exploited: CISA lists it, first on 14-01-2025. EPSS estimates a 10.07% chance of exploitation in the next 30 days, higher than 95.6% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 14-01-2025
   PublishedVulnerability first disclosed.
2. 14-01-2025
   Added to CISA KEVMicrosoft Windows Hyper-V NT Kernel Integration VSP Heap-based Buffer Overflow Vulnerability
3. 04-02-2025
   CISA remediation dueApply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
4. 09-06-2026
   Last modifiedVulnerability information updated.

Description

Windows Hyper-V NT Kernel Integration VSP Elevation of Privilege Vulnerability

• CWE-122Heap-based Buffer OverflowA heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().