CVE-2026-23565VulnerabilityPublished 29 Jan 2026

CVE-2026-23565: TeamViewer DEX · NULL Pointer Dereference

Affects TeamViewer DEXSource CVE Database V5

Not known to be exploited · CVSS 6.5 Medium : upgrade to 26.1 when convenient.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 3.1 base score

6.5Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.1% chance of exploitation in 30 days – higher than 8% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 26.1

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

Attack Vector: Adjacent
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: High

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Adjacent: The vulnerable component is bound to the network stack, but the attack is limited at the protocol level to a logically adjacent topology. This can mean an attack must be launched from the same shared physical (e.g., Bluetooth or IEEE 802.11) or logical (e.g., local IP subnet) network, or from within a secure or otherwise limited administrative domain (e.g., MPLS, secure VPN to an administrative network zone).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 29 Jan 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-25.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade TeamViewer DEX to 26.1.

Affected software

Product	Affected	Fixed in
TeamViewerDEX	Affected <26.1	Fixed in 26.1

AI-suggested

To mitigate CVE-2026-23565, European organizations should implement strict network segmentation and access controls to limit adjacent network access to the TeamViewer DEX Content Distribution Service. Employing firewall rules or VLAN segmentation can reduce exposure to potential attackers on the same network segment. Monitoring network traffic for anomalous or malformed requests targeting NomadBranch.exe may help detect exploitation attempts. If you cannot patch yet, consider temporarily disabling or restricting the Content Distribution Service if feasible, or isolating it within a secure network zone. Additionally, maintaining robust incident response plans and ensuring backups of critical systems can minimize operational impact in case of a denial-of-service event. Regularly reviewing and applying vendor advisories and security bulletins will ensure timely remediation.

Description

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 cause the NomadBranch.exe process to terminate via crafted requests. This can result in a denial-of-service condition of the Content Distribution Service.

Impact

For European organizations, the primary impact of CVE-2026-23565 is the potential denial-of-service of the TeamViewer DEX Content Distribution Service, which could interrupt software deployment and update distribution processes. This disruption may lead to delayed patching cycles, increased operational overhead, and potential exposure to other vulnerabilities due to outdated software. Organizations relying heavily on TeamViewer DEX for internal content distribution, especially in sectors like finance, healthcare, manufacturing, and critical infrastructure, could experience operational downtime or degraded service levels. Since the attack requires adjacent network access, segmented and well-controlled network environments reduce the risk. However, in environments with flat or poorly segmented networks, the vulnerability could be exploited by internal threat actors or lateral movement by attackers. The lack of confidentiality or integrity impact means data breaches are unlikely, but availability interruptions could indirectly affect business continuity and compliance with service-level agreements.

CWE-476NULL Pointer Dereference (opens in a new tab)
Base weaknessLikelihood of exploit: MediumCWE Top 25 (2025): #13OWASP Top 10 A10:2025: Mishandling of Exceptional Conditions (opens in a new tab)
The product dereferences a pointer that it expects to be valid but is NULL.
Implementation
For any pointers that could have been modified or provided from a function that can return NULL, check the pointer for NULL before use. When working with a multithreaded or otherwise asynchronous environment, ensure that proper locking APIs are used to lock before the check, and unlock when it has finished.
Requirements
Select a programming language that is not susceptible to these issues.
Implementation
Check the results of all functions that return a value and verify that the value is non-null before acting upon it.
OWASP Cheat Sheets
Logging (opens in a new tab)
Error Handling (opens in a new tab)
OWASP ASVS 4.0.3
V11.1.7 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

teamviewer.com/en/resources/trust-center/security-bulletins/tv-2026-1001/ (opens in a new tab)

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 29 Jan 2026, 09:29 UTC

WeaknessesCWE-476

Technical details

References

Community reviews

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