CVE-2025-54104 is a vulnerability categorized under CWE-843 (Access of Resource Using Incompatible Type, or 'Type Confusion') affecting the Windows Defender Firewall Service in Microsoft Windows 10 Version 1809 (build 10.0.17763.0). The flaw occurs when the firewall service improperly handles resource types, allowing an attacker who already has local authorized access with high privileges to exploit the type confusion to escalate their privileges further. This type confusion can lead to unauthorized access to sensitive resources or execution of code with elevated privileges, compromising system confidentiality, integrity, and availability. The attack vector is local, requiring the attacker to have some level of access (PR:H) but no user interaction (UI:N) is needed, making automated exploitation feasible once local access is gained. The vulnerability has a CVSS 3.1 base score of 6.7, reflecting medium severity due to the local attack vector and privilege requirements. No public exploits or patches are currently available, but the vulnerability is officially published and reserved as of mid-2025. The affected product is specifically Windows 10 Version 1809, which is an older Windows release still in use in some enterprise environments. The vulnerability's impact includes potential full system compromise if exploited successfully, as it affects core firewall service components responsible for network security. Given the nature of the vulnerability, it is primarily a local privilege escalation issue that could be chained with other exploits to achieve broader compromise.

For European organizations, the impact of CVE-2025-54104 can be significant, particularly for those still operating legacy Windows 10 Version 1809 systems. Successful exploitation allows attackers with local access to elevate privileges, potentially gaining administrative control over affected machines. This can lead to unauthorized access to sensitive data, disruption of network security controls enforced by the firewall service, and the ability to deploy further malware or lateral movement tools. Critical sectors such as government, finance, healthcare, and industrial control systems are particularly at risk due to the sensitive nature of their data and operations. The vulnerability undermines the integrity and availability of network defenses, increasing the risk of broader cyberattacks. Although exploitation requires local access and existing privileges, insider threats or attackers who have compromised lower-privileged accounts could leverage this flaw to escalate privileges and deepen their foothold. The lack of known exploits in the wild reduces immediate risk but does not eliminate the threat, especially as attackers often develop exploits post-disclosure. Organizations relying on Windows 10 1809 should prioritize mitigation to avoid potential compromise and cascading impacts on confidentiality, integrity, and availability.

1. Apply security patches and updates from Microsoft as soon as they become available for Windows 10 Version 1809 to address this vulnerability. 2. Restrict local administrative privileges to only trusted personnel and minimize the number of users with high privilege levels to reduce the attack surface. 3. Implement strict access controls and monitoring on endpoints running Windows 10 1809 to detect unusual privilege escalation attempts or suspicious activity related to the firewall service. 4. Consider upgrading legacy Windows 10 systems to supported versions with ongoing security updates to reduce exposure to known vulnerabilities. 5. Employ endpoint detection and response (EDR) solutions capable of identifying and alerting on local privilege escalation behaviors. 6. Conduct regular security audits and vulnerability assessments focusing on legacy systems to identify and remediate outdated software and configurations. 7. Enforce network segmentation and least privilege principles to limit the impact of a compromised host. 8. Educate IT staff and users about the risks of local privilege escalation and the importance of maintaining updated systems.