CVE-2025-54919 is a high-severity race condition vulnerability identified in the Windows 10 Version 1809 operating system, specifically within the Win32K graphics subsystem (GRFX). The vulnerability arises due to improper synchronization when concurrently accessing shared resources, classified under CWE-362. This race condition allows an authorized local attacker—someone with limited privileges and requiring user interaction—to execute arbitrary code with elevated privileges. The vulnerability affects Windows 10 build 17763.0 and involves concurrent execution paths that improperly manage access to shared memory or resources, leading to potential corruption or manipulation of critical system data structures. Exploiting this flaw could enable an attacker to escalate privileges, compromise system integrity, and gain control over the affected machine. The CVSS v3.1 base score is 7.5, reflecting high severity, with attack vector local, requiring high attack complexity, low privileges, and user interaction. The scope is changed, indicating that the vulnerability affects resources beyond the initially compromised component, with high impact on confidentiality, integrity, and availability. No known exploits are currently reported in the wild, and no patches have been linked yet, indicating that organizations should prioritize mitigation and monitoring. This vulnerability is particularly critical because Win32K is a core component of the Windows graphical subsystem, and exploitation could lead to full system compromise on affected Windows 10 1809 systems.

For European organizations, the impact of CVE-2025-54919 could be significant, especially for those still operating legacy Windows 10 Version 1809 systems. Successful exploitation could lead to local privilege escalation, allowing attackers to bypass security controls, install persistent malware, or move laterally within networks. This could compromise sensitive data confidentiality, disrupt business operations by affecting system availability, and undermine data integrity. Sectors with high reliance on Windows 10 1809, such as government agencies, critical infrastructure, healthcare, and financial institutions, may face increased risk of targeted attacks. The requirement for local access and user interaction somewhat limits remote exploitation but does not eliminate risk, as phishing or social engineering could facilitate initial access. Given the high impact on all security triad elements (confidentiality, integrity, availability), organizations could face regulatory consequences under GDPR if personal data is compromised. Additionally, the lack of available patches increases exposure time, emphasizing the need for proactive defenses.

1. Immediate mitigation should include restricting local user permissions to the minimum necessary to reduce the pool of potential attackers. 2. Implement strict application whitelisting and endpoint protection to detect and block suspicious local code execution attempts. 3. Employ enhanced user awareness training focused on preventing social engineering and phishing attacks that could lead to local access. 4. Monitor system logs and security telemetry for unusual Win32K subsystem activity or race condition exploitation indicators. 5. Where possible, upgrade affected systems from Windows 10 Version 1809 to a supported, patched Windows version to eliminate the vulnerability. 6. Use virtualization or sandboxing for high-risk user activities to contain potential exploitation. 7. Network segmentation can limit lateral movement if a local compromise occurs. 8. Maintain up-to-date backups and incident response plans tailored to local privilege escalation scenarios. 9. Engage with Microsoft security advisories regularly to apply patches promptly once available.