Pakistan's National CERT Flags High-Severity TeamViewer Flaw, Urges Immediate Update
National CERT has warned TeamViewer users in Pakistan to patch a high-severity integer overflow vulnerability (CVE-2026-111585, CVSS 8.8) affecting clients older than version 15.83 across Windows, macOS and Linux.
Pakistan's National Cyber Emergency Response Team (National CERT) has issued an advisory urging TeamViewer users to update the remote-access application after a high-severity security flaw was disclosed that could allow attackers to crash the software or execute malicious code on affected machines.
The vulnerability, tracked as CVE-2026-111585, carries a CVSS score of 8.8, placing it in the high-severity range. According to the advisory, which references TeamViewer's own security bulletin, the flaw affects TeamViewer clients older than version 15.83 running on Windows, macOS and Linux.
At the technical level, the bug is an integer overflow in the component of TeamViewer that processes remote screen data. A malicious or compromised remote computer can send specially crafted data that triggers the flaw, resulting in a crash or memory corruption. Depending on the platform involved, this could let an attacker execute code with the same privileges as the TeamViewer application itself.
Importantly, the attack is not automatic. It only succeeds when a user connects to a computer that is under the attacker's control, meaning the risk is highest for users who accept remote sessions from unknown or untrusted sources. The advisory lists the TeamViewer Full Client for Windows, macOS and Linux, TeamViewer Portable for Windows, and the Android Remote Control app among the affected products.
Users are advised to move to version 15.83 or later as soon as possible. Separate fixes have also been released for older branches, including version 14.7.48868 for the 14.x line and 13.2.36231 for the 13.x line, allowing organizations that cannot upgrade immediately to remain protected.
Where patching is not immediately feasible, National CERT recommends blocking untrusted remote connections as a stopgap measure. If a device is suspected of being compromised, organizations should preserve relevant logs, restrict remote access and seek assistance from incident-response professionals. The advisory follows other recent security guidance from National CERT aimed at protecting staff and organizations from emerging digital threats.
