CVE-2026-23567 identifies a heap-based buffer overflow vulnerability in the TeamViewer DEX Client's Content Distribution Service component, specifically in the UDP command handler of NomadBranch.exe prior to version 26.1 on Windows platforms. The root cause is an integer underflow that occurs when processing certain UDP packets, which leads to improper memory allocation or indexing, allowing an attacker on the adjacent network to overflow a heap buffer. This overflow can cause the service to crash, resulting in a denial-of-service condition. The vulnerability does not affect confidentiality or integrity, as it does not allow code execution or data manipulation, but it impacts availability by crashing the service. Exploitation requires no privileges or user interaction but does require the attacker to be on the adjacent network segment to send malicious UDP packets. No public exploits have been observed, and no patches are currently linked, indicating that remediation may be pending or in progress. The CVSS v3.1 score of 6.5 reflects a medium severity due to the ease of exploitation and impact on availability without affecting confidentiality or integrity. The vulnerability is classified under CWE-122 (Heap-based Buffer Overflow), a common memory corruption issue that can lead to crashes or potentially more severe consequences if exploited differently. Organizations using TeamViewer DEX for remote access or content distribution on Windows should be aware of this risk and prepare to apply updates once released.

For European organizations, the primary impact is service disruption due to denial-of-service caused by the crash of the TeamViewer DEX Content Distribution Service. This can interrupt remote management, content distribution, or other operational processes relying on TeamViewer DEX, potentially affecting business continuity. Since the vulnerability does not compromise data confidentiality or integrity, the risk of data breaches is low. However, availability interruptions can affect IT support, remote work capabilities, and automated content delivery, which are critical in sectors like finance, manufacturing, and public services. Organizations with extensive remote infrastructure or those relying heavily on TeamViewer DEX for operational tasks may experience operational delays or increased support costs. The requirement for adjacent network access limits the attack surface to local network environments or VPNs, reducing remote exploitation risk but emphasizing the need for internal network security. No known exploits in the wild reduce immediate risk but do not eliminate the threat, especially as attackers may develop exploits post-disclosure.

1. Monitor TeamViewer communications and network traffic for unusual or malformed UDP packets targeting NomadBranch.exe. 2. Restrict UDP traffic to and from TeamViewer DEX clients to trusted and necessary network segments only, using firewall rules or network segmentation to limit adjacent network exposure. 3. Prepare to apply the official patch or update to TeamViewer DEX version 26.1 or later as soon as it becomes available from the vendor. 4. Implement network intrusion detection systems (NIDS) with signatures or anomaly detection for suspicious UDP traffic patterns related to this vulnerability. 5. Conduct internal network audits to ensure that only authorized devices have access to the network segments where TeamViewer DEX operates. 6. Educate IT staff about the vulnerability and ensure incident response plans include steps for handling potential service crashes related to this issue. 7. Consider temporary disabling or limiting the use of the Content Distribution Service component if feasible until patched. 8. Maintain regular backups and system monitoring to quickly recover from potential denial-of-service incidents.