CVE-2025-53155 is a heap-based buffer overflow vulnerability identified in Microsoft Windows 10 Version 1809, specifically affecting the Windows Hyper-V component. This vulnerability, classified under CWE-122, allows an authorized local attacker with limited privileges to execute a privilege escalation attack. The flaw arises due to improper handling of memory buffers in the Hyper-V virtualization service, which can be exploited to overwrite heap memory, potentially leading to arbitrary code execution with elevated privileges. The attacker does not require user interaction to exploit this vulnerability, but must have local access and some level of privileges (PR:L). The vulnerability impacts confidentiality, integrity, and availability, as successful exploitation can lead to full system compromise. The CVSS v3.1 base score is 7.8, indicating a high severity level. No known exploits are currently reported in the wild, and no official patches have been linked yet. Given the affected version is Windows 10 Version 1809 (build 10.0.17763.0), which is an older release, systems still running this version remain at risk until mitigations or updates are applied. The vulnerability's exploitation vector is local (AV:L), meaning remote exploitation is not feasible without prior access. The vulnerability's scope is unchanged (S:U), so the impact is confined to the vulnerable component and does not extend beyond the security boundary of the Hyper-V service.

For European organizations, this vulnerability poses a significant risk, especially for enterprises and service providers utilizing Windows 10 Version 1809 with Hyper-V virtualization. Successful exploitation could allow attackers to escalate privileges from a limited user context to SYSTEM level, enabling them to deploy malware, access sensitive data, or disrupt critical services. This is particularly concerning for organizations relying on Hyper-V for virtualized environments, including cloud service providers, financial institutions, healthcare providers, and government agencies. The potential for full system compromise could lead to data breaches, operational downtime, and regulatory non-compliance under GDPR and other data protection laws. Since the vulnerability requires local access, insider threats or attackers who have gained initial footholds via other means (e.g., phishing, lateral movement) could leverage this flaw to deepen their control. The absence of known exploits in the wild currently reduces immediate risk, but the high severity and lack of patches necessitate proactive measures to prevent exploitation.

Given the absence of official patches, European organizations should implement the following specific mitigations: 1) Upgrade or migrate systems from Windows 10 Version 1809 to a supported and patched Windows version to eliminate exposure. 2) Restrict local access to systems running Hyper-V by enforcing strict access controls, including limiting administrative privileges and using just-in-time access models. 3) Employ application whitelisting and endpoint detection and response (EDR) solutions to monitor and block suspicious activities indicative of privilege escalation attempts. 4) Harden Hyper-V configurations by disabling unnecessary features and services, and applying security best practices for virtualization environments. 5) Conduct regular audits and monitoring of user activities and system logs to detect anomalous behavior early. 6) Educate internal users about the risks of local privilege escalation and enforce strong authentication mechanisms to reduce the risk of unauthorized local access. 7) Prepare incident response plans specifically addressing privilege escalation scenarios to enable rapid containment if exploitation is detected.