CVE-2025-54094 is a vulnerability classified under CWE-843 (Access of Resource Using Incompatible Type, commonly known as type confusion) affecting the Windows Defender Firewall Service in 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 or incompatible type, leading to undefined behavior that attackers can exploit to manipulate program execution. In this case, the flaw allows an attacker with authorized local access and high privileges to escalate their privileges further by exploiting the type confusion flaw within the firewall service. The vulnerability impacts confidentiality, integrity, and availability by potentially allowing attackers to execute arbitrary code or modify system settings at a higher privilege level. The CVSS v3.1 score of 6.7 reflects a medium severity, considering the attack vector is local, requires low complexity, and high privileges but no user interaction. No public exploits or patches are currently available, indicating the vulnerability is newly disclosed and unmitigated. This vulnerability primarily affects legacy Windows 10 systems, which may still be operational in certain organizations, especially those with strict upgrade cycles or legacy application dependencies. The Windows Defender Firewall Service is a critical security component, and exploitation could undermine system defenses, making this a significant concern for affected environments.

The vulnerability enables local privilege escalation, allowing attackers who already have some level of authorized access to gain higher privileges, potentially SYSTEM-level. This can lead to full system compromise, enabling attackers to disable security controls, install persistent malware, or access sensitive data. The impact on confidentiality, integrity, and availability is high once exploited. Although exploitation requires local access with high privileges, the ability to elevate privileges further can facilitate lateral movement and deeper compromise within an organization’s network. Organizations relying on Windows 10 Version 1507, particularly in critical infrastructure, government, or enterprise environments, face increased risk of targeted attacks or insider threats leveraging this flaw. The absence of patches increases the window of exposure, and the lack of known exploits suggests attackers may still be developing techniques to leverage this vulnerability.

1. Upgrade affected systems from Windows 10 Version 1507 to a supported and fully patched version of Windows 10 or later to eliminate exposure to this vulnerability. 2. If immediate upgrade is not feasible, restrict local access to affected systems by enforcing strict access controls and monitoring for unusual privilege escalation attempts. 3. Employ endpoint detection and response (EDR) solutions to detect anomalous behavior related to privilege escalation or firewall service manipulation. 4. Harden the Windows Defender Firewall Service configuration and audit related logs for suspicious activity. 5. Implement the principle of least privilege to minimize the number of users with high privileges on affected systems. 6. Monitor vendor advisories closely for patches or workarounds and apply them promptly once available. 7. Conduct regular vulnerability assessments and penetration testing focusing on privilege escalation vectors in legacy systems. 8. Educate system administrators about the risks of legacy OS usage and encourage timely system updates.