CVE-2026-23563 is a vulnerability classified under CWE-59 (Improper Link Resolution Before File Access) affecting TeamViewer DEX, specifically the 1E Client component on Windows platforms prior to version 26.1. The flaw arises from the way the application handles file deletion instructions invoked by the 1E-Explorer-TachyonCore-DeleteFileByPath RPC command. When processing this instruction, the software improperly resolves symbolic links or junction points created by a low-privileged local attacker. This improper link resolution allows the attacker to redirect the delete operation to protected system files, which normally would be inaccessible or protected from deletion. The vulnerability requires the attacker to have local privileges and to interact with the system to create the crafted RPC control junction or symlink. The CVSS v3.1 score is 5.7 (medium severity), reflecting the need for local privileges and user interaction, as well as the high complexity of the attack. The impact primarily affects system integrity and availability by enabling deletion of critical system files, potentially leading to system instability or denial of service. There are no known public exploits or patches available at the time of publication, emphasizing the need for proactive mitigation. This vulnerability is particularly relevant for environments where TeamViewer DEX is deployed on Windows endpoints, especially in enterprise settings where the 1E Client is used for endpoint management and automation.

For European organizations, this vulnerability poses a risk to the integrity and availability of Windows systems running vulnerable versions of TeamViewer DEX. Successful exploitation could lead to deletion of critical system files, causing system crashes, service disruptions, or denial of service conditions. This can impact business continuity, especially in sectors relying heavily on endpoint management tools such as finance, healthcare, manufacturing, and government. Since the attack requires local access and privileges, insider threats or compromised user accounts pose a significant risk vector. The inability to maintain system stability could also affect compliance with European regulations on operational resilience and data protection. Additionally, the disruption of endpoint management capabilities could delay incident response and remediation efforts, amplifying the operational impact.

European organizations should immediately verify their TeamViewer DEX version and upgrade to version 26.1 or later once available. Until patches are released, restrict local user privileges to the minimum necessary, preventing untrusted users from creating junctions or symbolic links in directories accessible to the 1E Client. Implement strict application whitelisting and endpoint protection to detect and block suspicious RPC commands or unauthorized file system modifications. Regularly audit and monitor file system changes and RPC activity related to the 1E Client. Employ host-based intrusion detection systems (HIDS) to alert on attempts to create or manipulate junctions or symlinks in sensitive paths. Educate system administrators and users about the risks of local privilege misuse and enforce strong access controls. Coordinate with TeamViewer support for any interim mitigation guidance and monitor for official patches or updates. Finally, integrate this vulnerability into vulnerability management and incident response workflows to ensure timely detection and remediation.