TeamViewer flaw: National CERT tells users in Pakistan to update to version 15.83 now

Pakistan's National CERT has told everyone using TeamViewer to update the remote-access app straight away. A high-severity flaw, tracked as CVE-2026-111585 with a CVSS score of 8.8 out of 10, can let a hostile computer crash TeamViewer or run its own code on yours. Every TeamViewer client older than version 15.83 on Windows, macOS and Linux is affected, the advisory says, citing TeamViewer's own security bulletin, ProPakistani reported on Sunday evening.

TeamViewer is the default tool for remote support in Pakistani offices, banks' IT desks, freelancers working for foreign clients and families helping parents fix a laptop from another city, so the warning reaches far beyond IT departments.

How the TeamViewer attack works

The bug is an integer overflow in the part of TeamViewer that handles incoming remote screen data. A malicious or hacked computer at the other end of a session can send data that triggers it. The result is a crash or memory corruption, and on some platforms that can let the attacker run code with the same rights as TeamViewer itself.

The important limit: the attack is not automatic. It only works when you connect to a computer the attacker controls. A cold call from someone posing as "bank support" or a "freelance client" who asks you to join their TeamViewer session is exactly the route this flaw would use.

Which versions are affected

According to the advisory:

• TeamViewer Full Client for Windows, macOS and Linux
• TeamViewer Portable for Windows
• The Android Remote Control app

What to do now

1. Update. Open TeamViewer, go to Help, then Check for new version, and install it. On Android, update from the Play Store. Do not forget portable copies on USB drives and old office PCs.
2. Only join sessions with people you know. Never connect to a stranger's TeamViewer ID because a caller asked you to.
3. Review unattended access. Offices should check which machines accept unattended connections and who has admin rights, and remove anything not needed.
4. Watch for warning signs. Unexpected TeamViewer crashes or sessions you did not start should be reported to your IT team.
5. If you cannot patch yet, National CERT suggests blocking remote connections from untrusted sources. If a device may already be compromised, keep its logs, cut remote access and get incident-response help.

Why it matters for freelancers

Pakistan's freelancers often install whatever remote tool a new client asks for. A fake "client" who wants you to connect to their machine is a known scam pattern, and this flaw gives it teeth. If you earn from abroad, keep your tools updated and keep your tax side in order too: our freelancer tax calculator shows what you owe on foreign income.

National CERT publishes its advisories on pkcert.gov.pk; TeamViewer lists its fixes in its security bulletins.