CVE-2025-29824 is a high-severity use-after-free vulnerability identified in the Windows Common Log File System (CLFS) driver on Microsoft Windows 10 Version 1809 (build 10.0.17763.0). The vulnerability is classified under CWE-416, which pertains to use-after-free errors where a program continues to use memory after it has been freed, potentially leading to memory corruption. In this case, the flaw exists within the CLFS driver, a core component responsible for managing log files used by various Windows subsystems and applications. An authorized attacker with local access and low privileges can exploit this vulnerability to elevate their privileges on the affected system. The CVSS v3.1 base score is 7.8, indicating a high severity, with the vector string CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C. This means the attack requires local access (AV:L), low attack complexity (AC:L), and low privileges (PR:L), but no user interaction (UI:N). The impact on confidentiality, integrity, and availability is high (C:H/I:H/A:H), and the exploit code is functional (E:F) with official remediation (RL:O) and confirmed fix (RC:C). Although no known exploits are currently reported in the wild, the presence of a functional exploit elevates the risk. The vulnerability allows an attacker to manipulate memory in the CLFS driver, potentially executing arbitrary code or causing system crashes, thereby compromising system security and stability. Since Windows 10 Version 1809 is an older release, many organizations may have moved to newer versions, but legacy systems or those with delayed patching remain at risk. The absence of published patches at the time of this report necessitates immediate attention to monitor for updates and apply mitigations.

For European organizations, this vulnerability poses a significant risk, especially for those running legacy Windows 10 Version 1809 systems in critical environments such as government, healthcare, finance, and industrial control systems. Successful exploitation can lead to local privilege escalation, allowing attackers to gain SYSTEM-level access from a low-privileged user account. This can facilitate further lateral movement, data exfiltration, deployment of ransomware, or disruption of services. The high impact on confidentiality, integrity, and availability means sensitive data could be exposed or altered, and critical services could be interrupted. Organizations with strict regulatory requirements under GDPR and other data protection laws face potential compliance violations and reputational damage if exploited. The local attack vector limits remote exploitation but insider threats or compromised user accounts could leverage this vulnerability. The lack of user interaction requirement increases the risk of automated or stealthy exploitation once local access is obtained.

Given the absence of an official patch at the time of disclosure, European organizations should implement the following specific mitigations: 1) Restrict local access to systems running Windows 10 Version 1809 by enforcing strict access controls and monitoring for unauthorized logins. 2) Employ application whitelisting and endpoint detection and response (EDR) solutions to detect anomalous behavior indicative of exploitation attempts targeting the CLFS driver. 3) Disable or limit the use of CLFS-dependent applications if feasible, or isolate affected systems in segmented network zones to reduce lateral movement risk. 4) Enforce the principle of least privilege rigorously, ensuring users operate with minimal necessary rights to reduce the attack surface. 5) Monitor Windows event logs and system behavior for signs of memory corruption or unexpected crashes related to CLFS. 6) Prepare for rapid deployment of patches once released by Microsoft and test updates in controlled environments before wide deployment. 7) Educate IT staff and users about the risks of local privilege escalation vulnerabilities and the importance of maintaining updated systems. 8) Consider upgrading affected systems to supported Windows versions with active security updates to reduce exposure to legacy vulnerabilities.