Filed under: Cybersecurity · Patching · September 2026

What happened

On September 29, TeamViewer released version 15.82 to fix five serious security holes in its Full Client and Host apps for Windows, Mac, and Linux. The worst one (CVE-2026-92370) could let an attacker get around TeamViewer’s session permission checks and run their own code on the computer. The other four could let someone who already has a foothold on a PC take full administrator (SYSTEM) control. TeamViewer says it has seen no attacks using these flaws yet and no public exploit code exists. For now, this is a patch-it-before-it-matters situation, not an emergency.

Why it matters to your business

TeamViewer is on a lot of small business computers. Sometimes staff installed it to work from home, sometimes a software vendor set it up years ago to provide support, and sometimes it sits on a front-desk PC that nobody thinks about. Ransomware gangs have a long history of using TeamViewer to get into business networks. Once a fix like this is published, attackers study it to learn how to attack the older versions that haven’t been updated.

What to do this week

1. Find every copy. On each Windows PC, open Settings → Apps → Installed apps and search for “TeamViewer.” Check Macs too. Don’t forget “TeamViewer Host,” which runs quietly in the background on unattended machines.
2. Check the version. In TeamViewer, go to Help → About TeamViewer (in the newer interface, look under the ⋯ menu or Settings). Anything below 15.82 needs updating.
3. Update. Use Help → Check for new version, or download 15.82 from teamviewer.com and install it over the old version. If your IT provider manages TeamViewer centrally, ask them to confirm every device is on 15.82.
4. Remove it where no one uses it. If a PC has TeamViewer that nobody can explain, uninstall it. A remote-access tool you don’t use is just an unlocked door.
5. Lock down the accounts you keep. Turn on two-factor authentication for your TeamViewer account, and set unattended access to trusted accounts only (Settings → Security).

The bigger picture

Remote-access tools are some of the most valuable software attackers can target, because they’re built to let someone in from anywhere. Keeping an up-to-date list of what’s installed on your PCs, and patching on a schedule instead of waiting for trouble, is what heads off an incident like this. → Proactive vs. Reactive IT Management: Lessons from Healthcare for SMBs

Not sure which remote-access tools are running on your office PCs? Book a free consult → https://micro1tech.com/contact/