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Digital Employee ExperienceApplication · Teamviewer

CVE-2026-23566

MEDIUM · 6.5 CVSS v3.1 Published 2026-01-29
Fix available
A fix is available. Upgrade to 26.1 or later.
See remediation →
70/100
Remediation priority · Elevated
No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

A vulnerability in TeamViewer DEX Client's Content Distribution Service (NomadBranch.exe) allows an adjacent network attacker to inject, tamper with, or forge log entries in Nomad Branch.log by sending crafted UDP packets to the network handler, compromising log integrity and nonrepudiation.

MitigationUpgrade to TeamViewer DEX Client version 26.1 or later to obtain the patch, and consider network segmentation to limit adjacent network access to the UDP handler.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Digital Employee ExperienceApplication
Affected:< 26.1

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Adjacent
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Confirm TeamViewer DEX Client installation
    Check Program Files or Program Files (x86) for a TeamViewer folder, or search for NomadBranch.exe on the system using: dir /s /b C:\NomadBranch.exe 2>nul or find / -name NomadBranch.exe 2>/dev/null
    Affected if TeamViewer DEX Client or NomadBranch.exe is not found on the system, the vulnerability does not apply
  2. Identify installed TeamViewer DEX version
    Check the version of the TeamViewer DEX Client installation. Look in the application's About or Help section, check the installed program's version property in Windows Programs and Features, or examine the version info of the NomadBranch.exe file by right-clicking the file, selecting Properties, and reviewing the Details tab
    Affected if The installed version is lower than 26.1 (for example, 25.x, 24.x, or any version number below 26.1)
  3. Verify NomadBranch.exe process is running
    Open Task Manager or use command: tasklist /FI "IMAGENAME eq NomadBranch.exe" to check if the Content Distribution Service process is active
    Affected if NomadBranch.exe is not running, the attack surface is not currently exposed even if a vulnerable version is installed
  4. Check for UDP network listeners
    Use netstat -an | findstr UDP or a network monitoring tool to identify if the service is bound to UDP ports. Also check Windows Firewall rules or third-party firewall logs for inbound UDP traffic to the TeamViewer service
    Affected if UDP ports are open and listening, the network handler that accepts the crafted packets is active and exposed to adjacent network attackers

The system is affected if TeamViewer DEX Client version is below 26.1, NomadBranch.exe is installed and running, and the service has an active UDP listener that could receive crafted packets from the adjacent network.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 26.1 or later
Fixed in 26.1
Interim mitigation

Upgrade to TeamViewer DEX Client version 26.1 or later to obtain the patch, and consider network segmentation to limit adjacent network access to the UDP handler.

Recommended fix High confidence

Version 26.1 or later of TeamViewer DEX Client (1E Client) for Windows

  1. Identify all systems running TeamViewer DEX Client (formerly 1E Client) with NomadBranch.exe component
  2. Check current version of the software on each affected system (must be below 26.1)
  3. Obtain the fixed version 26.1 or later from the official TeamViewer download source
  4. Plan and schedule the upgrade during a planned maintenance window
  5. Back up current configuration settings if applicable
  6. Deploy the version 26.1 update to all affected Windows systems
  7. Verify the upgrade was successful by checking the NomadBranch.exe version
  8. Confirm the Content Distribution Service is running correctly after upgrade

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Digital Employee Experience Scoped from the published advisory
  • Consultation2.0 h
  • Implementation1.0 h
  • Testing2.0 h
  • Review / QA1.0 h
6.0 hours of engineering $1,060
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-23566 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data