CVE-2025-44002 is a medium-severity vulnerability classified as a Time-of-check Time-of-use (TOCTOU) race condition affecting the TeamViewer Full Client and Host versions prior to 15.69 on Windows platforms. The flaw resides in the directory validation logic, where a local non-administrative user can exploit a timing window during the verification of directories by manipulating symbolic links. This manipulation allows the attacker to create arbitrary files with SYSTEM-level privileges. The vulnerability arises because the software checks the directory state (time-of-check) and then uses it (time-of-use) without ensuring the directory has not been altered in between, enabling a race condition. Exploiting this vulnerability does not require user interaction but does require local access with limited privileges. The impact primarily involves the creation of files with elevated privileges, which can lead to denial-of-service (DoS) conditions by overwriting or corrupting critical files or potentially enabling privilege escalation paths. The CVSS 3.1 base score of 6.1 reflects a medium severity, with attack vector local, low attack complexity, low privileges required, no user interaction, unchanged scope, no confidentiality impact, limited integrity impact, and high availability impact. No known exploits are reported in the wild yet, and no patches are currently linked, indicating that mitigation may rely on vendor updates or workarounds.

For European organizations, this vulnerability poses a significant risk especially in environments where TeamViewer is widely used for remote support and administration. The ability for a local non-admin user to escalate privileges to SYSTEM level could allow insider threats or compromised local accounts to disrupt critical systems, leading to denial-of-service conditions. This could affect operational continuity, particularly in sectors relying heavily on remote access tools such as IT services, healthcare, finance, and manufacturing. The lack of confidentiality impact reduces the risk of data breaches directly from this flaw, but the integrity and availability impacts could cause system instability or downtime. Given the widespread use of TeamViewer across Europe, organizations with less stringent endpoint security controls or those that allow multiple users on shared machines are at higher risk. The vulnerability also raises concerns for compliance with European data protection and operational resilience regulations, as service interruptions could lead to regulatory scrutiny.

Immediate mitigation should focus on restricting local user permissions to the minimum necessary and monitoring for unusual file system activity, especially symbolic link creation or modification in directories used by TeamViewer. Organizations should enforce strict endpoint security policies, including application whitelisting and integrity monitoring. Until an official patch is released, consider disabling or limiting TeamViewer usage on critical systems or replacing it with alternative remote access solutions with no known vulnerabilities. Regularly audit user accounts to remove unnecessary local access and implement robust logging to detect potential exploitation attempts. Network segmentation can limit the impact of compromised hosts. Once TeamViewer releases a patch, prioritize its deployment across all affected systems. Additionally, educating users about the risks of local privilege escalation and maintaining updated antivirus and endpoint detection and response (EDR) solutions can help detect and prevent exploitation attempts.