CVE-2025-55224 is a race condition vulnerability classified under CWE-362, found in the Win32K graphics subsystem of Microsoft Windows 10 Version 1809 (build 10.0.17763.0). The flaw arises from improper synchronization when multiple threads concurrently access shared resources, leading to a state where an attacker can execute arbitrary code locally. Specifically, the vulnerability exists in the graphics (GRFX) component of Win32K, a core part of the Windows kernel-mode driver responsible for graphical operations. An authorized attacker with low privileges (PR:L) can exploit this race condition without requiring user interaction (UI:N), but must have local access to the system. The attack complexity is high (AC:H), indicating exploitation requires precise timing and conditions. The vulnerability has a CVSS v3.1 base score of 7.8, reflecting high impact on confidentiality, integrity, and availability (all rated high). The scope is changed (S:C), meaning the vulnerability can affect resources beyond the initially vulnerable component, potentially leading to full system compromise. No known exploits are currently in the wild, and no official patches have been released at the time of publication. The vulnerability was reserved on August 11, 2025, and published on September 9, 2025. Due to the nature of the flaw, successful exploitation could allow privilege escalation and arbitrary code execution within the kernel context, posing severe risks to affected systems.

For European organizations, this vulnerability poses a significant threat, particularly to those still operating legacy systems running Windows 10 Version 1809. The ability for a low-privileged local attacker to escalate privileges and execute arbitrary code can lead to full system compromise, data breaches, and disruption of critical services. Sectors such as government, finance, healthcare, and critical infrastructure are especially at risk due to their reliance on Windows-based systems and the sensitivity of their data. The vulnerability could be leveraged for lateral movement within networks, enabling attackers to gain persistent access and potentially disrupt operations or exfiltrate sensitive information. Given the high impact on confidentiality, integrity, and availability, exploitation could result in severe operational and reputational damage. The absence of known exploits in the wild currently reduces immediate risk but also underscores the urgency for proactive mitigation before potential weaponization occurs.

1. Upgrade affected systems to a supported and patched version of Windows, preferably the latest Windows 10 or Windows 11 releases, as Windows 10 Version 1809 is out of mainstream support. 2. Monitor Microsoft security advisories closely for the release of official patches addressing CVE-2025-55224 and apply them immediately upon availability. 3. Restrict local access to systems running Windows 10 Version 1809 by enforcing strict access controls, limiting user privileges, and employing endpoint protection solutions that can detect anomalous behavior indicative of exploitation attempts. 4. Implement application whitelisting and kernel-mode code signing policies to prevent unauthorized code execution. 5. Conduct regular security audits and vulnerability assessments to identify and remediate legacy systems still in use. 6. Employ advanced endpoint detection and response (EDR) tools capable of monitoring kernel-level activities to detect exploitation attempts early. 7. Educate IT staff and users about the risks of running unsupported OS versions and the importance of timely updates. 8. Consider network segmentation to limit the impact of a compromised endpoint and prevent lateral movement within the network.