SB2025011444 - Multiple privilege escalation vulnerabilities in Microsoft Windows Hyper-V NT Kernel Integration VSP

Description

This security bulletin contains information about 3 vulnerabilities.

1) Heap-based buffer overflow (CVE-ID: CVE-2025-21333)

CWE-ID: CWE-122 - Heap-based Buffer Overflow

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:A/U:Amber

The vulnerability allows a local user to escalate privileges on the system.

The vulnerability exists due to a boundary error in Windows Hyper-V NT Kernel Integration VSP component. A local user can trigger a heap-based buffer overflow and execute arbitrary code with SYSTEM privileges.

Note, the vulnerability is being actively exploited in the wild.

2) Use-after-free (CVE-ID: CVE-2025-21334)

CWE-ID: CWE-416 - Use After Free

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:A/U:Amber

The vulnerability allows a local user to escalate privileges on the system.

The vulnerability exists due to a use-after-free error in Windows Hyper-V NT Kernel Integration VSP component. A local user can execute arbitrary code with SYSTEM privileges.

Note, the vulnerability is being actively exploited in the wild.

3) Use-after-free (CVE-ID: CVE-2025-21335)

CWE-ID: CWE-416 - Use After Free

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:A/U:Amber

The vulnerability allows a local user to escalate privileges on the system.

The vulnerability exists due to a use-after-free error in Windows Hyper-V NT Kernel Integration VSP component. A local user can execute arbitrary code with SYSTEM privileges.

Note, the vulnerability is being actively exploited in the wild.

Remediation

Install update from vendor's website.

References

• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2025-21333
• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2025-21334
• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2025-21335