PT-2026-26988 · Uvnc · Ultravnc Viewer

Victor Mondragón · Published 2026-03-22 · Updated 2026-03-22 · CVE-2019-25600

Positive Technologies (AI Summary)

CVSS v3.1

6.5

Medium

Base vector

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

Name of the Vulnerable Software and Affected Versions UltraVNC Viewer version 1.2.2.4

Description A denial of service issue exists where attackers can crash the application by supplying an oversized string to the VNC Server input field. By pasting a malicious string containing 256 repeated characters into the VNC Server field and clicking Connect, a buffer overflow is triggered, causing the viewer to crash.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.

Exploit

Memory Corruption

Weakness Enumeration

CWE-787

Related Identifiers

CVE-2019-25600

Affected Products

Ultravnc Viewer

References · 5

• 🔥 https://exploit-db.com/exploits/46702 · Exploit
• https://nvd.nist.gov/vuln/detail/CVE-2019-25600 · Security Note
• https://vulncheck.com/advisories/ultravnc-viewer-denial-of-service-via-buffer-overflow · Note
• https://uvnc.com · Note
• https://uvnc.com/downloads/ultravnc/126-download-ultravnc-1224.html · Note