CVE-2025-62456 is a heap-based buffer overflow vulnerability identified in the Windows Resilient File System (ReFS) component of Microsoft Windows 11 Version 25H2 (build 10.0.26200.0). The vulnerability is classified under CWE-122, indicating improper memory handling that leads to buffer overflow on the heap. An attacker with authorized network access and low privileges can exploit this flaw to execute arbitrary code remotely, potentially gaining control over the affected system. The vulnerability does not require user interaction, increasing its risk profile. The CVSS v3.1 score of 8.8 (AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H) indicates network attack vector, low attack complexity, required privileges at a low level, no user interaction, and high impact on confidentiality, integrity, and availability. The flaw resides in how ReFS processes certain inputs, leading to memory corruption and enabling code execution. No patches or known exploits are currently publicly available, but the vulnerability is officially published and should be addressed promptly. The vulnerability's exploitation could allow attackers to compromise systems remotely, disrupt services, or exfiltrate sensitive data, especially in environments where ReFS is used for data storage and management.

For European organizations, the impact of CVE-2025-62456 is significant due to the widespread adoption of Windows 11 in enterprise environments and the use of ReFS in data centers and critical infrastructure. Successful exploitation could lead to full system compromise, allowing attackers to execute arbitrary code, steal sensitive information, disrupt operations, or deploy ransomware. This poses a threat to confidentiality, integrity, and availability of critical systems. Sectors such as finance, healthcare, government, and industrial control systems are particularly vulnerable due to their reliance on secure and resilient file systems. The network-based attack vector means that attackers can exploit this vulnerability remotely, increasing the risk of widespread attacks across organizational networks. The lack of known exploits currently provides a window for proactive mitigation, but the high severity score demands immediate attention to prevent potential future exploitation.

1. Monitor Microsoft security advisories closely and apply official patches or updates for Windows 11 Version 25H2 as soon as they become available. 2. Restrict network access to systems using ReFS, especially limiting exposure of ReFS services to untrusted networks or segments. 3. Implement network segmentation and firewall rules to reduce the attack surface and isolate critical systems. 4. Employ intrusion detection and prevention systems (IDS/IPS) to monitor for anomalous activity related to ReFS or suspicious network traffic patterns. 5. Conduct regular security audits and vulnerability assessments focusing on Windows 11 systems and ReFS usage. 6. Educate system administrators about the vulnerability and ensure least privilege principles are enforced to limit the impact of compromised accounts. 7. Maintain comprehensive backups of critical data stored on ReFS volumes to enable recovery in case of compromise. 8. Consider disabling ReFS on systems where it is not required or feasible to mitigate risk until patches are applied.