CVE-2025-62467 is a vulnerability identified in the Windows Projected File System (ProjFS) component of Microsoft Windows 11 Version 25H2 (build 10.0.26200.0). The flaw is caused by an integer overflow or wraparound condition, classified under CWE-190, which occurs when arithmetic operations exceed the maximum size of an integer variable, causing it to wrap around to a smaller value. This can lead to improper memory handling or logic errors within the ProjFS component. ProjFS is a kernel-mode file system filter that allows applications to project hierarchical data into the file system namespace. An attacker with authorized local access and limited privileges can exploit this vulnerability to escalate their privileges to SYSTEM or equivalent, thereby gaining full control over the affected system. The vulnerability does not require user interaction and has a low attack complexity, but it does require local access and some level of privilege. The CVSS v3.1 base score of 7.8 reflects a high severity due to the potential for complete compromise of confidentiality, integrity, and availability. Currently, there are no known public exploits or patches available, indicating that organizations should prepare for imminent remediation. The vulnerability was reserved on October 14, 2025, and published on December 9, 2025. Given the critical role of ProjFS in Windows 11's file system operations, exploitation could allow attackers to bypass security controls and execute arbitrary code with elevated privileges.

For European organizations, this vulnerability poses a significant threat, especially in environments where Windows 11 Version 25H2 is widely deployed. Successful exploitation could lead to unauthorized access to sensitive data, disruption of critical services, and potential lateral movement within networks. Organizations in sectors such as finance, healthcare, government, and critical infrastructure are particularly at risk due to the potential for full system compromise. The local privilege escalation aspect means that attackers who have gained limited access—through phishing, insider threats, or other means—could leverage this flaw to gain administrative control, bypassing existing security restrictions. This elevates the risk of data breaches, ransomware deployment, and sabotage. The absence of known exploits currently provides a window for proactive defense, but the high severity score underscores the urgency for mitigation. Additionally, the vulnerability could impact endpoint security solutions and other software relying on ProjFS, potentially undermining layered defenses.

1. Restrict local access to systems running Windows 11 Version 25H2 by enforcing strict access controls and limiting user privileges to the minimum necessary. 2. Implement robust endpoint detection and response (EDR) solutions capable of monitoring for unusual privilege escalation attempts and anomalous behavior related to file system operations. 3. Enforce application whitelisting and use of least privilege principles to reduce the attack surface for local exploits. 4. Monitor system logs and audit events for signs of exploitation attempts targeting ProjFS or unusual privilege escalations. 5. Prepare for rapid deployment of official patches from Microsoft once released, including testing in controlled environments to avoid operational disruptions. 6. Educate IT staff and security teams about this vulnerability to ensure timely recognition and response. 7. Consider network segmentation to limit the impact of compromised endpoints and prevent lateral movement. 8. Review and harden local user account policies, including disabling or restricting unnecessary local accounts. 9. Maintain up-to-date backups and incident response plans to mitigate potential damage from exploitation.