1. Executive Summary
TeamViewer published security bulletin TV-2026-1011 on 27 October 2026, covering three high-severity vulnerabilities in client components, with a maximum CVSS score of 8.8. The vendor says the flaws are fixed in updated versions and that it was not aware of active exploitation at publication.
These are separate flaws, not one confirmed attack chain. They involve crafted screen-image data, integer-overflow handling in screen processing, and a local macOS package-handling weakness. Impact depends on platform, version, and user interaction.
2. Vulnerability Details
- CVE-2026-92372 (CVSS 8.8): Out-of-bounds write in the Linux/macOS Full Client screen-image decoder. Crafted screen data in a remote-control session or a specially crafted .tvs recording opened by a user could lead to code execution. User interaction is required.
- CVE-2026-111585 (CVSS 8.8): Integer overflow in remote-control screen processing could cause denial of service or potentially code execution with the viewer process’s privileges. The user must establish a session with an attacker-controlled or compromised host.
- CVE-2026-92374 (CVSS 7.8): A TOCTOU race condition and improper symbolic-link handling in the macOS privileged helper could allow a local low-privileged attacker to bypass package verification and install a malicious package, potentially gaining root.
3. Attack Flow
- Attacker prepares a malicious or compromised remote host, crafted screen data, or a malicious TeamViewer session recording.
- The target connects to the host or opens the recording, meeting the interaction requirement for the remote-processing flaws.
- Vulnerable screen-processing code handles malformed data, potentially causing a crash, memory corruption, or code execution.
- If successful, code runs with the TeamViewer viewer process’s privileges; the separate macOS flaw could permit root escalation.
- An attacker might attempt follow-on access to files or data available to that process. This is a potential consequence, not a reported outcome of these CVEs.
4. Flowchart
Malicious/compromised remote host or crafted .tvs file → victim connects/opens content → vulnerable decoder/decompression routine processes crafted data → crash or memory corruption → possible code execution → potential follow-on activity based on process privileges.
Separate macOS path: low-privileged local access → TOCTOU/symlink handling flaw → package verification bypass → malicious package install → possible root escalation. This is a conceptual reconstruction, not evidence of exploitation.
5. Affected Products and Remediation
The bulletin covers TeamViewer Remote, TeamViewer Tensor, and TeamViewer ONE product families. Vulnerable versions include releases before 15.83 for the relevant components; legacy branches are also listed. CVE-2026-111585 additionally affects TeamViewer Remote Control for Android prior to 15.83.
TeamViewer recommends updating to version 15.83 or the latest available version. Check legacy installations separately, obtain updates through official channels, avoid unexpected .tvs recordings, and connect only to verified remote hosts. Review remote-access logs and endpoint telemetry if compromise is suspected.
6. Impact, Attribution and Caveats
Successful code execution could expose data accessible to the affected process; root escalation on macOS would be more severe. However, the vendor reported no known active exploitation at publication and did not attribute the vulnerabilities to a threat actor. Do not infer data theft or a named campaign from the vulnerability disclosure alone.
7. Timeline
- 27 October 2026: TeamViewer published bulletin TV-2026-1011 and recommended updating.
- 28 October 2026: public reporting summarized the flaws and TeamViewer 15.83.3 release.
- 29 September 2026: a separate TeamViewer bulletin TV-2026-1010 disclosed earlier client/service vulnerabilities; these are distinct disclosures.
8. Defensive Checklist
- Update TeamViewer clients, hosts, portable builds, and mobile apps to the latest supported version.
- Restrict remote access to approved devices and authenticated users; disable unattended access when unnecessary.
- Require MFA and centrally manage remote-access policies where possible.
- Train users not to open unexpected session recordings or accept unsolicited remote sessions.
- Monitor session logs, crashes, unusual process launches, and endpoint alerts; inventory versions and verify patching.
9. Conclusion
Remote-support software is a high-value trust boundary. Apply TeamViewer’s security updates promptly and treat unexpected remote sessions and session recordings with caution.
CyberRakshakLabs — Research | Awareness | Safer Digital India. https://cyberrakshaklabs.in/research/
10. Sources and Further Reading
- TeamViewer Trust Center, Security Bulletin TV-2026-1011: https://www.teamviewer.com/en/resources/trust-center/security-bulletins/tv-2026-1011/
- TeamViewer Security Bulletins: https://www.teamviewer.com/en/resources/trust-center/security-bulletins/
- PBX Science, 28 October 2026: https://pbxscience.com/teamviewer-15-83-3-released-fixing-nine-high-severity-vulnerabilities/