CVE-2025-49665 is a high-severity race condition vulnerability identified in Microsoft Windows 10 Version 1809, specifically in the Workspace Broker component. The vulnerability arises due to improper synchronization when concurrently accessing shared resources, classified under CWE-362 (Concurrent Execution using Shared Resource with Improper Synchronization). This flaw allows an authorized local attacker to exploit the race condition to elevate their privileges on the affected system. The attacker must have some level of local access (low privileges) but does not require user interaction to trigger the exploit. The vulnerability impacts confidentiality, integrity, and availability, as successful exploitation can lead to full system compromise by escalating privileges to higher levels, potentially SYSTEM or administrator. The CVSS v3.1 base score is 7.8, reflecting a high severity with attack vector local, low attack complexity, and no user interaction required. The scope remains unchanged, meaning the impact is confined to the vulnerable component or system. No known exploits are currently reported in the wild, and no patches have been linked yet, indicating that mitigation may require vendor updates or workarounds. The vulnerability affects Windows 10 Version 1809 build 10.0.17763.0, which is an older Windows 10 release, but still in use in some environments, especially in enterprise or industrial contexts where long-term servicing versions are preferred. The race condition could be exploited by an attacker to bypass security controls and gain elevated privileges, potentially allowing them to install malware, access sensitive data, or disrupt system operations.

For European organizations, this vulnerability poses a significant risk, particularly for those still running Windows 10 Version 1809 in production environments. Privilege escalation vulnerabilities are critical because they can be leveraged to gain administrative control over systems, enabling attackers to move laterally, deploy ransomware, or exfiltrate sensitive data. Sectors such as finance, healthcare, government, and critical infrastructure in Europe are especially at risk due to the potential impact on confidentiality and system integrity. The lack of a patch at the time of disclosure increases the window of exposure. Organizations with legacy systems or those that have delayed upgrading to newer Windows versions are more vulnerable. Additionally, compliance with GDPR and other European data protection regulations means that exploitation leading to data breaches could result in severe legal and financial penalties. The local attack vector limits remote exploitation but insider threats or attackers who gain initial footholds through phishing or other means could leverage this vulnerability to escalate privileges and deepen their access.

European organizations should prioritize identifying and inventorying all systems running Windows 10 Version 1809 to assess exposure. Immediate mitigation steps include applying any available security updates from Microsoft once released. Until patches are available, organizations should implement strict access controls to limit local user privileges and reduce the number of users with local access rights. Employing application whitelisting and endpoint detection and response (EDR) solutions can help detect suspicious privilege escalation attempts. Restricting the use of shared resources and monitoring Workspace Broker activity for anomalies may also reduce risk. Organizations should enforce the principle of least privilege and consider upgrading affected systems to supported Windows versions with active security support. Regularly auditing and hardening local accounts and services can further reduce the attack surface. Additionally, educating users about the risks of local privilege escalation and monitoring logs for unusual behavior can aid early detection.