TeamViewer Integer Overflow: Risks and Fixes

What happened

TeamViewer has addressed a flaw affecting Full Client, Portable (Windows), and Remote Control App (Android), along with the listed legacy and maintenance releases. Think of it like a counter that runs out of room and wraps around, leaving software working with the wrong value. Here, that counting problem occurs in the component that processes screens during remote-control sessions.

The vulnerability, CVE-2026-111585, can let a malicious remote host disrupt the application viewing its screen. Depending on the platform, it could also allow code to run with the permissions of that viewing application. A user must establish a remote-control session with an attacker-controlled or compromised host for exploitation to be possible.

The vendor's advisory identifies corrected releases for the affected product branches, while NVD published its entry on 2026-10-27. KISA, Korea's Internet & Security Agency, also published an advisory on 2026-11-02. The vulnerability is not listed in CISA KEV as of the check date; that catalog status does not establish whether exploitation has occurred.

Technical details

NVD classifies the weakness as CWE-190, Integer Overflow or Wraparound. An integer is a whole-number value stored within a limited range. An overflow occurs when a calculation exceeds that range, potentially producing an unexpected result. In this case, the flaw is in TeamViewer's remote-control screen processing component. The description does not identify the exact calculation or implementation mistake behind it.

The key attack precondition is the direction of the connection: a user must connect their TeamViewer client to an attacker-controlled or compromised remote host. The client viewing that host's screen is the application exposed to the flaw. The description does not support treating this as an attack that succeeds merely because TeamViewer is installed.

Possible consequences include denial of service, meaning disruption such as an application crash, and potentially arbitrary code execution on some platforms. Arbitrary code execution means an attacker may be able to make the affected application run code of their choosing. Any such code would run with the privileges of the viewer process, meaning the permissions held by the application displaying the remote screen. The description does not establish that every affected platform permits code execution.

NVD assigns a CVSS 3.1 score of 8.8 and a HIGH severity rating. CVSS is a standardized way to describe vulnerability severity; this rating supports prioritizing the update. It is not a measurement of how likely a particular user is to encounter an attack. The requirement to establish a remote-control session and the platform-dependent consequences remain central to understanding the risk.

Who is affected

Everyday users

For everyday users, the important scenario is using TeamViewer to view or control another device. If that remote device is controlled by an attacker or has been compromised, the session could expose the viewing application to this flaw. A crash could interrupt your work, while potential code execution would have more serious consequences within the application's permissions.

Check which TeamViewer product and release you actually use before choosing an update. Full Client, Portable (Windows), and Remote Control App (Android) have a fix at 15.83 and later, but the legacy and maintenance branches have their own corrected builds. An older branch needs to be checked against its specific entry.

Developers

Developers who use TeamViewer for troubleshooting or remote work should assess the client they connect from. The affected component handles the remote screen, so a development workstation can be exposed when its user connects to a malicious or compromised host. The advisory concerns TeamViewer clients; it does not establish a vulnerability in software you develop merely because TeamViewer is part of your workflow.

For junior developers, the useful technical lesson is that a numeric calculation error can have consequences beyond an incorrect displayed value. Here, an integer overflow in screen processing can disrupt the viewer and may allow code execution, depending on the platform. Without further implementation details, it would be speculative to attribute the flaw to a particular calculation, buffer, or programming language.

Server and IT admins

Server and IT admins should inventory the TeamViewer clients used to initiate support sessions, including Portable (Windows), Remote Control App (Android), and legacy or maintenance installations. Reviewing only the devices receiving remote support would miss the central exposure described here: the client that connects to and displays an untrusted remote host.

A mixed environment needs branch-specific update planning. Full Client Legacy/Maintenance (Windows 7 & 8) has a different corrected release from Full Client (Windows, Linux, macOS), and the 13.2 branch has separate corrected builds for Windows, macOS, and Linux. Record the product, platform, and installed version together so an update can be matched to the appropriate advisory entry.

What to do now

1. Identify every affected TeamViewer client you use or manage. Record its product name, platform, and installed version, including portable and Android clients used to start remote-control sessions.
2. For Full Client (Windows, Linux, macOS), Portable (Windows), and Remote Control App (Android) earlier than 15.83, update to 15.83 and later. Follow the update steps in the vendor's advisory.
3. For Full Client Legacy/Maintenance (Windows) in the 13.2 branch, use 13.2.36231 and later. For Full Client Legacy/Maintenance (macOS) in the 13.2 branch, use 13.2.154007 and later. For Full Client Legacy/Maintenance (Linux) in the 13.2 branch, use 13.2.154008 and later.
4. For Full Client Legacy/Maintenance (Windows, Linux, macOS) in the 14.7 branch, use 14.7.48868 and later. Follow the update steps in the vendor's advisory.
5. For Full Client Legacy/Maintenance (Windows 7 & 8) in the 15.64 branch, use 15.64.10 and later. Follow the update steps in the vendor's advisory.
6. Confirm the installed version after updating each client. In managed environments, track completion by product and branch so that a corrected release on one platform does not obscure an affected installation elsewhere.

How to confirm the fix

• Check the installed version of Full Client (Windows, Linux, macOS), Portable (Windows), and Remote Control App (Android) against the corrected release: 15.83 and later.
• For the 13.2 branch, confirm the platform-specific corrected build: 13.2.36231 and later for Windows, 13.2.154007 and later for macOS, or 13.2.154008 and later for Linux.
• For the 14.7 branch, confirm 14.7.48868 and later. For Full Client Legacy/Maintenance (Windows 7 & 8) in the 15.64 branch, confirm 15.64.10 and later.
• Reconcile your inventory with the vendor's advisory and confirm that the client actually used to initiate remote-control sessions is on its applicable corrected release. A session that completes without crashing is not proof that the vulnerability has been fixed.

NVD scores and CISA KEV status

As of November 2, 2026, none of these CVEs is listed in the CISA Known Exploited Vulnerabilities catalog.

Affected products and fixed versions 8 rows

The vendor's advisory is the authority on affected and fixed versions. If a cell says “See the vendor advisory”, check it there.

Frequently asked questions

References

• TeamViewer advisory: https://www.teamviewer.com/en/resources/trust-center/security-bulletins/tv-2026-1011/
• NVD: CVE-2026-111585
• CISA Known Exploited Vulnerabilities catalog
• Also reported by KISA (Korea Internet & Security Agency) on November 2, 2026: KISA advisory (Korean)

How this page is made: versions and CVE IDs come from the vendor advisory table; CVSS scores and weakness types from NVD; exploitation status only from CISA KEV. The explainer is written with AI from those facts and published only after an automated check matches every version, CVE, score and command against the sources. Commands are limited to ones in official documentation. Always follow the vendor's advisory. Read in Korean.