CVE-2025-21335: Windows Hyper-V NT Kernel Integration VSP Elevation of Privilege Vulnerability

CVE-2025-21335 is a critical use-after-free vulnerability identified in the Windows Hyper-V NT Kernel Integration Virtual Service Provider (VSP). This flaw allows local attackers to gain elevated SYSTEM privileges, potentially compromising the entire system.

What is Vulnerable to CVE-2025-21335

The vulnerability affects Windows systems utilizing Hyper-V with the NT Kernel Integration VSP component. Specific versions impacted include:

• Windows Server 2016
• Windows Server 2019
• Windows 10
• Windows 11

Systems with Hyper-V enabled are particularly at risk.

Mitigation and Remediation for CVE-2025-21335

To address this vulnerability, Microsoft has released security updates as part of their January 2025 Patch Tuesday. Administrators should:

1. Apply Security Updates:

   • Ensure all affected Windows systems are updated with the latest patches provided by Microsoft.

2. Verify Update Installation:

   • Confirm that the updates have been successfully installed and that systems are functioning as expected.

3. Monitor Systems:

   • Regularly check for unusual activity that may indicate attempted exploitation.

Detailed information and download links for the patches can be found on Microsoft’s official website.

Impact of Successful Exploitation of CVE-2025-21335

Exploiting this vulnerability allows attackers to:

• Gain SYSTEM Privileges:

  • Execute arbitrary code with the highest level of system access.

• Compromise System Integrity:

  • Install malicious software, alter system configurations, or exfiltrate sensitive data.

• Facilitate Lateral Movement:

  • Use the compromised system as a foothold to infiltrate other networked devices.

Given the severity, immediate remediation is crucial to protect organizational assets.

Proof of Concept for CVE-2025-21335

As of now, there is no publicly available proof-of-concept (PoC) exploit for CVE-2025-21335. However, reports indicate that this vulnerability has been actively exploited in the wild, emphasizing the need for prompt patching and system monitoring.

CVE-2025-21335 poses a significant threat to Windows systems running Hyper-V with the NT Kernel Integration VSP component. Administrators are urged to apply the necessary patches immediately and maintain vigilant monitoring to safeguard against potential exploitation. Staying informed through official advisories and ensuring systems are up-to-date are essential steps in maintaining robust cybersecurity defenses.