SB2026021079 - Multiple vulnerabilities in Microsoft Windows Hyper-V
Published: February 10, 2026
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 4 secuirty vulnerabilities.
1) Improper access control (CVE-ID: CVE-2026-21255)
The vulnerability allows a local user to gain unauthorized access to otherwise restricted functionality.
The vulnerability exists due to improper access restrictions in Windows Hyper-V. A local user can bypass implemented security restrictions and gain unauthorized access to the application.
2) Input validation error (CVE-ID: CVE-2026-21247)
The vulnerability allows a remote attacker to execute arbitrary code on the target system.
The vulnerability exists due to insufficient validation of user-supplied input in Windows Hyper-V. A remote user can trick a victim to load a specially crafted file and execute arbitrary code on the system.
3) Heap-based buffer overflow (CVE-ID: CVE-2026-21248)
The vulnerability allows a remote attacker to execute arbitrary code on the target system.
The vulnerability exists due to a boundary error in Windows Hyper-V. A remote user can trick a victim to load a specially crafted file, trigger a heap-based buffer overflow and execute arbitrary code on the target system.
Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.
4) Heap-based buffer overflow (CVE-ID: CVE-2026-21244)
The vulnerability allows a remote attacker to execute arbitrary code on the target system.
The vulnerability exists due to a boundary error in Windows Hyper-V. A remote user can trick a victim to load a specially crafted file, trigger a heap-based buffer overflow and execute arbitrary code on the target system.
Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.
Remediation
Install update from vendor's website.