What is CVE-2026-23566?

CVE-2026-23566 is a medium-severity vulnerability in Microsoft Windows, classified under Improper Input Validation. CVSS score: 6.5/10. Published 2026-01-29.

How severe is CVE-2026-23566?

Medium severity. CVSS v3 base score is 6.5 out of 10.

Improper input validation in Microsoft Windows

CVE-2026-23566

A vulnerability in TeamViewer DEX Client (former 1E Client) - Content Distribution Service (NomadBranch.exe) prior version 26.1 for Windows allows an attacker on the adjacent network to inject, tamper with, or forge log entries in \Nomad Branch.log via crafted data sent to the UDP network handler. This can impact log integrity and nonrepudiation.

Vulnerability class: Drupalgeddon 2 (CVE-2018-7600)

EPSS: 0.002 (6.5th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N.

Affected products

Weakness classification (CWE)

CWE-20 — Improper Input Validation

References

psirt@teamviewer.com (Vendor Advisory)

Frequently asked questions

What is CVE-2026-23566?: CVE-2026-23566 is a medium-severity vulnerability in Microsoft Windows, classified under Improper Input Validation. CVSS score: 6.5/10. Published 2026-01-29.
How severe is CVE-2026-23566?: Medium severity. CVSS v3 base score is 6.5 out of 10.