CVE-2025-21340 in Windows
Summary
by MITRE • 01/14/2025
Windows Virtualization-Based Security (VBS) Security Feature Bypass Vulnerability
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Analysis
by VulDB Data Team • 05/23/2026
This vulnerability represents a critical security flaw in Windows Virtualization-Based Security mechanisms that allows adversaries to bypass essential protection controls designed to safeguard system integrity. The issue stems from insufficient validation of virtualization-based security features within the Windows operating system, creating potential attack vectors for malicious actors seeking to undermine the security posture of protected environments. Such vulnerabilities directly impact the fundamental security model that relies on hardware virtualization to isolate and protect critical system components from malicious interference.
The technical flaw manifests in the improper handling of security feature validation processes within the Windows kernel, specifically affecting how virtualization-based security components verify their operational status and enforce protection policies. Attackers can exploit this weakness to disable or circumvent security features that should remain active during system operation, effectively neutralizing the protections provided by Windows Defender Application Control, Credential Guard, and other virtualization-based security mechanisms. This bypass occurs at the hypervisor level where the security features are supposed to maintain their integrity and enforcement capabilities.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass complete compromise of the security infrastructure that organizations rely upon for protection against advanced persistent threats. Systems running affected Windows versions become vulnerable to attacks that can bypass memory protection mechanisms, disable secure boot processes, and undermine the isolation properties that virtualization-based security provides. This creates opportunities for attackers to execute malicious code within protected environments while evading detection by traditional security controls that depend on virtualization-based protection layers.
Organizations should implement immediate mitigations including deploying the latest security patches from Microsoft, enabling additional security controls such as Windows Defender Application Control policies, and implementing network-based monitoring to detect suspicious behavior patterns. The vulnerability aligns with CWE-284 Access Control Issues and maps to ATT&CK technique T1055 Process Injection, where adversaries leverage system-level access to manipulate security features. Security teams must also consider implementing additional layers of protection including endpoint detection and response solutions, network segmentation, and regular security assessments to identify potential exploitation attempts. The remediation process requires careful planning to ensure that security features are properly re-enabled after patching while maintaining system stability and operational continuity.