CVE-2020-37134 MEDIUM

CVE-2020-37134: UltraVNC Viewer 1.2.4.0 - 'VNCServer' Denial of Service

Vendor Ultravnc Team
Product UltraVNC Viewer
Weakness CWE-770 · Uncontrolled resource consumption
Published February 5, 2026
Last update March 5, 2026
View on NVD All CVEs

CVSS base score

4.6/10
Attack vector Local
Attack complexity Low
Privileges required None
User interaction —
Confidentiality —
Integrity —

CVSS vector

CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

February 5, 2026 CVE published
March 5, 2026 Record updated