CVE-2025-49751 is a vulnerability identified in Microsoft Windows 10 Version 1809 (build 10.0.17763.0) specifically affecting the Hyper-V virtualization platform. The root cause is a missing synchronization mechanism within Hyper-V, classified under CWE-820 (Missing Synchronization). This flaw creates a race condition that can be exploited by an attacker who already has authorized local access (low privilege requirement) to cause a denial of service (DoS) condition on an adjacent network segment. The vulnerability does not impact confidentiality or integrity but affects availability by potentially disrupting network services or virtual machine operations. The CVSS v3.1 base score is 6.8, reflecting medium severity with an attack vector requiring adjacent network access, low attack complexity, and no user interaction. The scope is changed (S:C), indicating that the vulnerability can affect resources beyond the initially compromised component. No public exploits have been reported yet, and no patches are currently linked, suggesting that mitigation is pending or in development. This vulnerability is particularly relevant in environments where Hyper-V is used for virtualization, as it could allow attackers to disrupt critical services or workloads running on virtual machines. The lack of synchronization likely leads to race conditions that cause resource conflicts or crashes, resulting in service outages. Given the widespread use of Windows 10 in enterprise environments and the popularity of Hyper-V for virtualization, this vulnerability poses a tangible risk to organizations relying on these technologies.

For European organizations, the primary impact of CVE-2025-49751 is the potential disruption of availability in virtualized environments running Windows 10 Version 1809 with Hyper-V enabled. This can lead to downtime of critical applications hosted on virtual machines, affecting business continuity and operational efficiency. Sectors such as finance, healthcare, manufacturing, and government that rely heavily on virtualization for workload isolation and resource optimization may experience service interruptions. The denial of service could also affect network segments adjacent to the compromised host, potentially impacting broader network operations. Since the vulnerability requires local authorized access, insider threats or compromised internal accounts pose a significant risk vector. The absence of confidentiality or integrity impact reduces the risk of data breaches but does not diminish the operational consequences of service outages. Organizations with legacy systems still running Windows 10 Version 1809 are particularly vulnerable, as newer Windows versions are not indicated as affected. The lack of known exploits in the wild provides a window for proactive mitigation, but the medium severity score underscores the need for timely response.

1. Apply security patches promptly once Microsoft releases them for CVE-2025-49751 to address the missing synchronization issue in Hyper-V. 2. Restrict local access to systems running Windows 10 Version 1809, especially those hosting Hyper-V, by enforcing strict access controls and monitoring privileged accounts. 3. Implement network segmentation to limit the impact of potential denial of service attacks on adjacent networks. 4. Monitor Hyper-V logs and network traffic for unusual activity or signs of race condition exploitation attempts. 5. Consider upgrading affected systems to a more recent Windows version where this vulnerability is not present or has been resolved. 6. Employ endpoint detection and response (EDR) solutions capable of detecting anomalous behavior related to virtualization components. 7. Educate internal users and administrators about the risks of local privilege misuse and enforce the principle of least privilege. 8. Conduct regular vulnerability assessments and penetration tests focusing on virtualization infrastructure to identify and remediate weaknesses.