CVE-2019-25600

high

Description

UltraVNC Viewer 1.2.2.4 contains a denial of service vulnerability that allows attackers to crash the application by supplying an oversized string to the VNC Server input field. Attackers can paste a malicious string containing 256 repeated characters into the VNC Server field and click Connect to trigger a buffer overflow that crashes the viewer.

References

https://www.vulncheck.com/advisories/ultravnc-viewer-denial-of-service-via-buffer-overflow

https://www.uvnc.com/downloads/ultravnc/126-download-ultravnc-1224.html

https://www.uvnc.com/

https://www.exploit-db.com/exploits/46702

Details

Source: Mitre, NVD

Published: 2026-03-22

Updated: 2026-03-22

Risk Information

CVSS v2

Base Score: 7.8

Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:C

Severity: High

CVSS v3

Base Score: 6.5

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

Severity: Medium

CVSS v4

Base Score: 7.1

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

Severity: High