CVE-2020-37134: Ultravnc Team Ultravnc Viewer

High severity, CVSS 7.5. EPSS: 0.4% chance of exploitation in the next 30 days.

UltraVNC Viewer 1.2.4.0 contains a denial of service vulnerability that allows attackers to crash the application by manipulating VNC Server input. Attackers can generate a malformed 256-byte payload and paste it into the VNC Server connection dialog to trigger an application crash.

Affected products

Published 2026-02-05. Last modified 2026-06-17.