CVE-2025-49660 is a high-severity use-after-free vulnerability identified in Microsoft Windows 10 Version 1809 (build 10.0.17763.0). The flaw exists within the Windows Event Tracing component, a system service responsible for logging and tracing system and application events. A use-after-free vulnerability occurs when a program continues to use a pointer after the memory it points to has been freed, potentially leading to memory corruption, arbitrary code execution, or privilege escalation. In this case, an authorized local attacker with limited privileges can exploit this vulnerability to elevate their privileges to a higher level, potentially SYSTEM or administrative privileges. The CVSS 3.1 base score of 7.8 reflects a high severity, with the vector indicating local attack vector (AV:L), low attack complexity (AC:L), requiring privileges (PR:L), no user interaction (UI:N), unchanged scope (S:U), and high impact on confidentiality, integrity, and availability (C:H/I:H/A:H). No known exploits in the wild have been reported yet, and no patches have been linked at the time of publication. The vulnerability was reserved in June 2025 and published in July 2025. The lack of user interaction and low complexity make this vulnerability particularly dangerous in environments where users have limited privileges but access to the vulnerable system. Exploitation could allow attackers to bypass security boundaries and gain full control over affected systems, enabling further lateral movement, data theft, or system disruption.

For European organizations, this vulnerability poses a significant risk, especially in enterprises and government agencies still running Windows 10 Version 1809, which, despite being an older release, may remain in use due to legacy application dependencies or delayed upgrade cycles. Successful exploitation could lead to unauthorized privilege escalation, allowing attackers to execute malicious code with elevated rights, access sensitive data, or disrupt critical services. This is particularly concerning for sectors with stringent data protection requirements under GDPR, such as finance, healthcare, and public administration. The ability to elevate privileges locally could facilitate insider threats or post-compromise escalation following initial access via other means. Additionally, the high impact on confidentiality, integrity, and availability could result in data breaches, operational downtime, and reputational damage. Since no public exploits are currently known, proactive mitigation is crucial to prevent attackers from developing and deploying exploit code targeting this vulnerability.

European organizations should prioritize upgrading affected systems to a supported and patched version of Windows 10 or later. If immediate upgrading is not feasible, organizations should implement strict access controls to limit local user privileges, ensuring that only trusted personnel have access to vulnerable systems. Employ application whitelisting and endpoint detection and response (EDR) solutions to monitor and block suspicious activities indicative of exploitation attempts. Regularly audit and restrict the use of Windows Event Tracing where possible, and consider disabling or limiting tracing features if not required for operational purposes. Network segmentation can help contain potential compromises by limiting lateral movement from exploited hosts. Additionally, maintain up-to-date backups and incident response plans to quickly recover from potential attacks. Monitoring security advisories from Microsoft for patches or workarounds related to CVE-2025-49660 is essential to apply fixes promptly once available.