CVE-2025-48813 is a vulnerability classified under CWE-324, which relates to the use of cryptographic keys beyond their expiration date. Specifically, in Windows 11 Version 25H2 (build 10.0.26200.0), Virtual Secure Mode (VSM) improperly allows the use of expired keys. VSM is a security feature that isolates sensitive processes and data using hardware virtualization and hypervisor protections. The flaw enables an attacker with local authorized access and low privileges to exploit the expired key usage to perform spoofing attacks, potentially impersonating legitimate processes or credentials. The attack complexity is high, requiring specific conditions and privileges, and no user interaction is needed. The vulnerability impacts confidentiality and integrity but does not affect system availability. Although no public exploits are known, the vulnerability's presence in a widely deployed OS version necessitates attention. The lack of a patch link indicates that remediation may still be pending or in progress.

For European organizations, this vulnerability could lead to unauthorized privilege escalation or identity spoofing within critical systems running Windows 11 Version 25H2. Confidential data protected by VSM could be exposed or manipulated, undermining trust in system integrity. Sectors with high security requirements, such as finance, healthcare, and government, may face increased risks of targeted local attacks, especially in environments where multiple users have local access or where endpoint security controls are lax. Although the attack requires local access and high complexity, insider threats or malware that gains limited local privileges could exploit this flaw to escalate their capabilities. The absence of availability impact reduces the likelihood of denial-of-service scenarios but does not diminish the risk to data confidentiality and integrity.

Organizations should monitor Microsoft security advisories closely for the release of an official patch addressing CVE-2025-48813 and apply it promptly. In the interim, restrict local access to systems running the affected Windows 11 version to trusted personnel only. Implement strict key lifecycle management policies, ensuring cryptographic keys are rotated and invalidated correctly within VSM and related components. Employ endpoint detection and response (EDR) solutions to detect anomalous local activities indicative of spoofing attempts. Harden privilege management by enforcing the principle of least privilege and using multi-factor authentication for local accounts where feasible. Additionally, conduct regular audits of cryptographic key usage and system logs to identify potential misuse of expired keys. Consider isolating critical systems or using virtualization-based security features with updated configurations to minimize exposure.