A vulnerability in TeamViewer DEX Client (former 1E client) - Content Distribution Service…
CVE-2025-44016 is a high-severity improper input validation vulnerability in DEX from TeamViewer, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited from the same local network by an unauthenticated attacker, without any action from a user. The record lists version 25.11.0.29 as the first without the flaw, so updating DEX to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.31% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update DEX to 25.11.0.29 or a later version.
- Update Digital Employee Experience to 25.11 or a later version.
- Read the advisory on teamviewer.com for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| TeamViewer | DEX | before 25.11.0.29; 25.9.0.46 and earlier; 25.5.0.53 and earlier; 24.5.0.69 and earlier | 25.11.0.29 |
| Teamviewer | Digital Employee Experience | before 25.11 | 25.11 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- AdjacentThe attacker must be on the same local network segment.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by CNA (teamviewer.com).
Official description
A vulnerability in TeamViewer DEX Client (former 1E client) - Content Distribution Service (NomadBranch.exe) prior version 25.11 for Windows allows malicious actors to bypass file integrity validation via a crafted request. By providing a valid hash for a malicious file, an attacker can cause the service to incorrectly validate and process the file as trusted, enabling arbitrary code execution under the Nomad Branch service context.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Input Validation
The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.
How developers prevent this class of flaw
- Consider using language-theoretic security (LangSec) techniques that characterize inputs using a formal language and build recognizers for that language. This effectively requires parsing to be a distinct layer that effectively enforces a boundary between raw input and internal data representations, instead of allowing parser code to be scattered throughout the program, where it could be subject to errors or inconsistencies that create weaknesses.
- Use an input validation framework such as Struts or the OWASP ESAPI Validation API. Note that using a framework does not automatically address all input validation problems; be mindful of weaknesses that could arise from misusing the framework itself (CWE-1173).
- Understand all the potential areas where untrusted inputs can enter the product, including but not limited to: parameters or arguments, cookies, anything read from the network, environment variables, reverse DNS lookups, query results, request headers, URL components, e-mail, files, filenames, databases, and any external systems that provide data to the application. Remember that such inputs may be obtained indirectly through API calls.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Other vulnerabilities in DEX
- 7.5 High severity
- 8.1 High severity
- 7.1 High severity
- 7.2 High severity
- 7.2 High severity
- 7.2 High severity
Recent Improper Input Validation vulnerabilities
- 7.8 High severity
- 7.2 High severity
- 7.2 High severity
- 8.4 High severity
- 9.1 Critical severity
- 7.5 High severity
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