National CERT urges TeamViewer users to update over serious flaw

The National Cyber Emergency Response Team (National CERT) has urged users of the TeamViewer remote-access app to update it after a high-severity security flaw was found, ProPakistani reported.

The flaw is tracked as CVE-2026-111585 and carries a CVSS score of 8.8. According to the advisory, it affects TeamViewer clients older than version 15.83 on Windows, macOS and Linux. The advisory lists TeamViewer Full Client for Windows, macOS and Linux, TeamViewer Portable for Windows, and the Android Remote Control app as affected.

The bug is an integer overflow in the part of TeamViewer that processes remote screen data. A malicious or hacked remote computer can send data that triggers it, causing a crash or memory corruption. Depending on the platform, an attacker could run code with the same privileges as the TeamViewer app.

The attack is not automatic. It only works when a user connects to a computer controlled by the attacker.

Users should move to version 15.83 or later. Older branches have separate fixes, including 14.7.48868 for the 14.x line and 13.2.36231 for the 13.x line.

National CERT advised users and organizations to update all TeamViewer installations, including portable and older versions. It also advised accepting remote sessions only from verified, trusted people, limiting remote access to approved users and devices, and reviewing unattended access and admin privileges.

Users should also watch for unexpected TeamViewer crashes or unusual sessions. Where patching is not immediately possible, the advisory suggests blocking untrusted remote connections.

If a device may be compromised, organizations should preserve logs, restrict remote access and seek incident-response help, according to the advisory.