CVE-2025-54104 is a vulnerability classified under CWE-843 (Access of Resource Using Incompatible Type, also known as type confusion) affecting the Windows Defender Firewall Service on Microsoft Windows 10 Version 1507 (build 10.0.10240.0). Type confusion vulnerabilities occur when a program accesses a resource or object using an incorrect type, leading to unexpected behavior, memory corruption, or privilege escalation. In this case, the vulnerability allows an authorized attacker with local access and high privileges to exploit the Windows Defender Firewall Service to elevate their privileges further on the system. The flaw arises from improper handling of resource types within the firewall service, enabling the attacker to manipulate internal data structures or processes to gain higher system privileges. The CVSS v3.1 score of 6.7 reflects a medium severity level, with attack vector limited to local (AV:L), low attack complexity (AC:L), requiring privileges (PR:H), no user interaction (UI:N), unchanged scope (S:U), and high impact on confidentiality, integrity, and availability (C:H/I:H/A:H). No public exploits or proof-of-concept code have been reported yet, and no patches are currently linked, indicating the vulnerability is newly disclosed and may require vendor action. This vulnerability primarily affects legacy Windows 10 systems that are no longer widely supported or updated, increasing risk for organizations still running this version. The Windows Defender Firewall Service is a critical security component, so exploitation could undermine system defenses and lead to full system compromise.

The potential impact of CVE-2025-54104 is significant for organizations still operating Windows 10 Version 1507 systems. Successful exploitation allows an attacker with existing local access and elevated privileges to further escalate their privileges, potentially gaining SYSTEM-level control. This can lead to complete compromise of affected machines, unauthorized access to sensitive data, disruption of firewall protections, and the ability to install persistent malware or move laterally within networks. Since the vulnerability affects a core security service (Windows Defender Firewall), exploitation could disable or bypass firewall rules, exposing the system to external threats. Although the attack requires local access and high privileges, insider threats, compromised accounts, or attackers leveraging other vulnerabilities could chain exploits to leverage this flaw. Organizations relying on legacy Windows 10 systems in critical infrastructure, government, or enterprise environments face increased risk of targeted attacks aiming to gain full control over affected endpoints. The lack of known exploits currently limits immediate widespread impact, but the medium severity rating and high impact on confidentiality, integrity, and availability warrant prompt mitigation.

To mitigate CVE-2025-54104, organizations should first identify and inventory all systems running Windows 10 Version 1507 (build 10.0.10240.0). Given the age and limited support for this version, the most effective mitigation is to upgrade affected systems to a supported and fully patched Windows 10 or Windows 11 version. If upgrading is not immediately feasible, organizations should restrict local access to affected machines by enforcing strict access controls, limiting administrative privileges, and monitoring for suspicious local activity. Employ application whitelisting and endpoint detection and response (EDR) tools to detect abnormal behavior related to the Windows Defender Firewall Service. Network segmentation can reduce the risk of lateral movement from compromised endpoints. Additionally, monitor Windows event logs for anomalies in firewall service behavior. Since no patches are currently available, organizations should stay alert for vendor updates and apply them promptly once released. Avoid running unnecessary services and minimize the attack surface on legacy systems. Finally, conduct regular security awareness training to reduce insider threats and credential compromise risks.