CVE-2025-49751 is a vulnerability identified in Microsoft Windows 10 Version 1809, specifically related to the Windows Hyper-V virtualization component. The root cause is a missing synchronization mechanism, classified under CWE-820 (Missing Synchronization). This flaw allows an authorized attacker with low privileges (PR:L) and no user interaction (UI:N) to cause a denial of service (DoS) condition over an adjacent network. The vulnerability impacts the availability of the system but does not affect confidentiality or integrity. The attack vector is adjacent network (AV:A), meaning the attacker must have access to the same or a logically adjacent network segment. The scope is changed (S:C), indicating that the vulnerability affects resources beyond the initially vulnerable component, potentially impacting other system components or virtual machines managed by Hyper-V. The CVSS v3.1 base score is 6.8, categorized as medium severity. No known exploits are currently reported in the wild, and no patches have been linked yet. The vulnerability could be exploited by an attacker to disrupt services hosted on Hyper-V virtual machines or the host system itself, causing downtime or interruption of critical services running in virtualized environments.

For European organizations, this vulnerability poses a risk primarily to environments running Windows 10 Version 1809 with Hyper-V enabled, especially in sectors relying on virtualization for critical infrastructure, such as finance, healthcare, and government. A successful DoS attack could disrupt business continuity by making virtualized services unavailable, impacting operational efficiency and potentially causing financial losses. Since the attack requires network adjacency and low privileges, insider threats or compromised devices within the same network segment could exploit this vulnerability. The scope change means that the impact could extend beyond a single virtual machine, potentially affecting multiple services or tenants in multi-tenant environments. Given the widespread use of Windows 10 and Hyper-V in enterprise settings across Europe, the vulnerability could affect data centers, cloud service providers, and private enterprise networks, leading to service outages and reputational damage.

Organizations should prioritize upgrading or patching affected systems once Microsoft releases an official fix. In the interim, network segmentation should be enforced to limit adjacency exposure, restricting access to Hyper-V hosts and management interfaces to trusted devices only. Monitoring network traffic for unusual patterns around Hyper-V hosts can help detect exploitation attempts. Applying strict access controls and limiting the number of users with privileges to interact with Hyper-V environments reduces the attack surface. Additionally, organizations should consider disabling Hyper-V on Windows 10 Version 1809 systems if virtualization is not required. Regular vulnerability scanning and asset inventory to identify systems running the affected version will aid in targeted mitigation. Implementing network-level protections such as firewalls and intrusion detection/prevention systems configured to monitor and block suspicious adjacent network traffic can further reduce risk.