CVE-2025-53810 is a vulnerability classified under CWE-843 (Access of Resource Using Incompatible Type, commonly known as type confusion) found in the Windows Defender Firewall Service on Microsoft Windows 10 Version 1809 (build 10.0.17763.0). The flaw arises when the firewall service improperly handles data types, allowing an attacker with authorized local access to confuse the system about the type of resource being accessed. This type confusion can lead to elevation of privileges, enabling the attacker to execute code or actions with higher privileges than intended. The vulnerability does not require user interaction but does require the attacker to have some level of local privileges already, such as a standard user account. The CVSS v3.1 score is 6.7, reflecting medium severity, with high impact on confidentiality, integrity, and availability (C, I, A all rated high). The attack vector is local (AV:L), with low attack complexity (AC:L), and privileges required are high (PR:H). No public exploits have been reported yet, and no patches are currently linked, indicating that mitigation may rely on upcoming security updates from Microsoft. The vulnerability is significant because the Windows Defender Firewall Service is a core security component, and exploitation could undermine system defenses and allow further compromise.

For European organizations, this vulnerability poses a risk primarily to systems still running Windows 10 Version 1809, which is an older but still in-use OS version in some enterprises and public sector environments. Successful exploitation could allow attackers with local access to escalate privileges, potentially leading to full system compromise, data breaches, or disruption of critical services. This is particularly concerning for organizations handling sensitive data or critical infrastructure, such as government agencies, financial institutions, healthcare providers, and industrial control systems. The compromise of firewall service privileges could also facilitate lateral movement within networks and disable security controls, increasing the attack surface. Although no known exploits exist yet, the medium severity and high impact on confidentiality, integrity, and availability mean that organizations should proactively address this vulnerability to avoid future exploitation.

1. Prioritize upgrading or patching Windows 10 Version 1809 systems as soon as Microsoft releases a security update addressing CVE-2025-53810. 2. Restrict local access to systems running this OS version by enforcing strict access controls and limiting user privileges to the minimum necessary. 3. Implement application whitelisting and endpoint detection and response (EDR) solutions to monitor for unusual activity related to the Windows Defender Firewall Service. 4. Conduct regular audits of user accounts and permissions to reduce the risk of unauthorized local access. 5. Where possible, migrate legacy systems to supported Windows versions with ongoing security support. 6. Employ network segmentation to contain potential compromises and limit lateral movement. 7. Monitor security advisories from Microsoft and threat intelligence sources for updates or emerging exploit activity related to this vulnerability.