CVE-2025-55223 is a high-severity race condition vulnerability identified in the Graphics Kernel component of Microsoft Windows 10 Version 1809 (build 10.0.17763.0). The flaw arises from improper synchronization during concurrent execution when accessing shared resources, classified under CWE-362 (Concurrent Execution using Shared Resource with Improper Synchronization). This race condition can be exploited by an authorized local attacker with low privileges to elevate their privileges to a higher level, potentially SYSTEM or administrative privileges. The vulnerability does not require user interaction but does require local access and some level of privilege (PR:L). The attack complexity is high (AC:H), indicating that exploitation requires specific conditions or timing, but successful exploitation can lead to full compromise of confidentiality, integrity, and availability of the affected system. The CVSS v3.1 base score is 7.0, reflecting the significant impact on confidentiality, integrity, and availability (all rated high), but mitigated somewhat by the need for local access and higher attack complexity. There are no known exploits in the wild at the time of publication, and no patches have been linked yet, indicating that organizations should prioritize monitoring and prepare for patch deployment once available. The vulnerability is particularly concerning because the Graphics Kernel is a core component that interacts closely with hardware and system processes, and exploitation could allow attackers to bypass security controls and execute arbitrary code with elevated privileges.

For European organizations, this vulnerability poses a significant risk, especially for enterprises and government agencies that rely on Windows 10 Version 1809 in their infrastructure. Privilege escalation vulnerabilities can be leveraged by attackers who have gained initial access through other means (e.g., phishing, malware) to deepen their foothold, move laterally, and exfiltrate sensitive data or disrupt operations. The high impact on confidentiality, integrity, and availability means that critical systems could be compromised, leading to data breaches, operational downtime, or ransomware deployment. Since Windows 10 Version 1809 is an older release, some organizations may still be using it due to legacy application dependencies or delayed upgrade cycles, increasing their exposure. The absence of known exploits currently reduces immediate risk but also means attackers may develop exploits rapidly once details are public. European organizations in sectors such as finance, healthcare, energy, and government, which are frequent targets of sophisticated attacks, should consider this vulnerability a priority for risk assessment and mitigation.

1. Immediate inventory and identification of all systems running Windows 10 Version 1809 (build 17763.0) within the organization to understand exposure. 2. Plan and expedite upgrade or migration to a supported and patched version of Windows 10 or Windows 11, as this version is outdated and may no longer receive security updates. 3. Until patches are available, implement strict local access controls and monitoring to detect unusual privilege escalation attempts, including enhanced logging of Graphics Kernel interactions and privilege changes. 4. Employ application whitelisting and endpoint detection and response (EDR) solutions to detect and block suspicious activities that could exploit this race condition. 5. Restrict and monitor use of accounts with local privileges, applying the principle of least privilege to reduce the attack surface. 6. Educate IT staff and users about the risks of privilege escalation and the importance of reporting suspicious system behavior. 7. Once Microsoft releases a patch, prioritize rapid testing and deployment across all affected systems to close the vulnerability promptly.