CVE-2019-25600

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.

Score

CVSS 4.0 7.1 High

Status

Deferred - disclosure@vulncheck.com

Published

2026-03-22

Last modified

2026-03-24

Weaknesses

CWE-787

Affected products

• Ultravnc Viewer (Uvnc)

References

• https://www.exploit-db.com/exploits/46702
• https://www.uvnc.com/
• https://www.uvnc.com/downloads/ultravnc/126-download-ultravnc-1224.html
• https://www.vulncheck.com/advisories/ultravnc-viewer-denial-of-service-via-buffer-overflow