VulnerabilityPublished 29 Jan 2026

CVE-2026-23569: TeamViewer DEX · Out-of-bounds Read

Affects TeamViewer DEXSource CVE Database V5

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

Data as of 26 Oct 2026, 12:29 UTC

CVSS 3.1 base score

6.5Medium

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

EPSS: 0.3% chance of exploitation in 30 days – higher than 31% 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 26 Oct 2026.

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 or the CVSS exploit maturity 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

Immediate mitigation should focus on reducing exposure of the TeamViewer DEX Client's Content Distribution Service to untrusted networks. Network segmentation and firewall rules should restrict access to the NomadBranch.exe service to trusted hosts only. Employing intrusion detection and prevention systems (IDS/IPS) with signatures or anomaly detection for unusual requests targeting this service can help detect exploitation attempts. Organizations should monitor logs for crashes or unusual behavior of the TeamViewer DEX Client. If you cannot patch yet, consider disabling or uninstalling the affected component if feasible, or deploying application-layer gateways to filter and validate incoming requests. Regularly update endpoint protection solutions to detect potential exploitation attempts. Once TeamViewer releases a patch for version 26.1 or later, organizations must prioritize timely deployment. Additionally, conducting internal audits to inventory all systems running TeamViewer DEX Client will ensure comprehensive coverage of mitigation efforts. Educating IT staff about this vulnerability and its exploitation vectors will improve incident response readiness.

Description

An out-of-bounds read vulnerability in the TeamViewer DEX Client (former 1E Client) - Content Distribution Service (NomadBranch.exe) prior version 26.1 for Windows allows a remote attacker to leak stack memory and cause a denial of service via a crafted request. The leaked stack memory could be used to bypass ASLR remotely and facilitate exploitation of other vulnerabilities on the affected system.

Impact

For European organizations, this vulnerability poses a risk primarily to the availability and security posture of systems running TeamViewer DEX Client on Windows. The denial of service can disrupt remote management and content distribution workflows, potentially impacting business continuity, especially in environments relying heavily on remote administration. The memory leak aspect can aid attackers in bypassing ASLR, increasing the likelihood of successful exploitation of other vulnerabilities, which could lead to privilege escalation or remote code execution. Sectors such as finance, healthcare, manufacturing, and critical infrastructure that utilize TeamViewer for remote support and management are particularly vulnerable. The ability to exploit this vulnerability remotely without authentication broadens the attack surface, making exposed systems attractive targets for opportunistic attackers and advanced persistent threat groups. The absence of known exploits in the wild currently limits immediate widespread impact, but the vulnerability's characteristics suggest it could be weaponized in targeted attacks. European organizations must consider the potential for cascading effects from this vulnerability, especially in complex IT environments where multiple interdependent systems exist.

CWE-125Out-of-bounds Read (opens in a new tab)
Base weaknessCWE Top 25 (2025): #8
The product reads data past the end, or before the beginning, of the intended buffer.
Implementation · Input Validation
Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
Architecture and Design · Language Selection
Use a language that provides appropriate memory abstractions.
OWASP Cheat Sheets
XML Security (opens in a new tab)
Mass Assignment (opens in a new tab)
OWASP ASVS 4.0.3
V13.3.1 (opens in a new tab)
V5.1.4 (opens in a new tab)
V5.1.3 (opens in a new tab)
Attack patterns
Overread Buffers (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, 09:28 UTC

WeaknessesCWE-125

Technical details

References

Community reviews

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