CVE-2025-53149 is a heap-based buffer overflow vulnerability classified under CWE-122, located in the Kernel Streaming WOW Thunk Service Driver of Microsoft Windows 10 Version 1809 (build 10.0.17763.0). This driver component handles kernel streaming operations and the Windows-on-Windows (WOW) thunking mechanism, which facilitates compatibility between 32-bit and 64-bit processes. The vulnerability arises when the driver improperly manages heap memory, allowing an attacker with authorized local access to overflow a buffer on the heap. This overflow can corrupt adjacent memory structures, leading to arbitrary code execution within kernel mode. Exploiting this flaw enables an attacker to elevate privileges from a low-privileged user context to SYSTEM-level privileges, effectively gaining full control over the affected system. The CVSS v3.1 base score of 7.8 reflects high severity, with attack vector local (AV:L), low attack complexity (AC:L), requiring privileges (PR:L), no user interaction (UI:N), and impacts on confidentiality, integrity, and availability all rated high (C:H/I:H/A:H). No public exploits are known at this time, but the vulnerability's characteristics make it a prime candidate for future exploitation. The lack of available patches at publication heightens the urgency for mitigation. This vulnerability is particularly concerning for environments where Windows 10 Version 1809 remains in use, often due to legacy application dependencies or delayed upgrade cycles. The kernel-level nature of the flaw means successful exploitation can bypass most security controls, making it a critical risk for endpoint security.

For European organizations, the impact of CVE-2025-53149 is significant due to the potential for local privilege escalation leading to full system compromise. Confidentiality is at risk as attackers could access sensitive data stored on affected machines. Integrity is compromised because attackers can modify system files, configurations, or security settings. Availability is also threatened since attackers could disrupt system operations or deploy ransomware. Organizations relying on Windows 10 Version 1809, particularly in sectors like finance, healthcare, manufacturing, and government, may face increased risk due to the presence of legacy systems and critical infrastructure. The vulnerability could facilitate lateral movement within networks if attackers gain initial access to low-privileged accounts. The absence of known exploits currently provides a window for proactive defense, but the high severity score indicates that once exploits emerge, rapid exploitation could occur. This elevates the risk for European entities that have not yet migrated to newer Windows versions or applied mitigations. Additionally, compliance with EU data protection regulations (e.g., GDPR) could be jeopardized if breaches occur due to this vulnerability.

1. Prioritize upgrading affected systems from Windows 10 Version 1809 to a supported and patched Windows version to eliminate exposure. 2. Until upgrades are feasible, implement strict local access controls, limiting user permissions and restricting access to trusted personnel only. 3. Employ application whitelisting and endpoint detection and response (EDR) solutions to monitor for abnormal kernel-level activities indicative of exploitation attempts. 4. Harden systems by disabling unnecessary services and drivers related to kernel streaming if not required by business operations. 5. Conduct regular audits of local user accounts and privilege assignments to minimize the attack surface. 6. Monitor security advisories from Microsoft for the release of patches addressing this vulnerability and apply them immediately upon availability. 7. Implement network segmentation to contain potential lateral movement from compromised endpoints. 8. Educate IT staff and users about the risks of local privilege escalation vulnerabilities and the importance of maintaining updated systems. 9. Use virtualization-based security features available in newer Windows versions to isolate critical processes where possible. 10. Maintain comprehensive backups and incident response plans to recover quickly in case of exploitation.