UltraVNC Viewer Denial-of-Service Vulnerability

A denial-of-service vulnerability has been identified in UltraVNC Viewer version 1.2.4.0. This issue allows attackers to crash the application by manipulating input in the VNC Server connection dialog. Exploitation involves generating a malformed payload of 256 bytes, which can be pasted into the dialog to trigger the crash.

Impact

Exploitation of this vulnerability leads to a crash of the UltraVNC Viewer application.

Reproduction

To reproduce this vulnerability, first run a Python script that generates a 256-byte payload and saves it to a text file. Then, open UltraVNC Viewer and paste the payload from the text file into the VNC Server connection dialog. Click 'Connect' to trigger the application crash.