What is CVE-2019-25600?

CVE-2019-25600 is a medium-severity vulnerability in Uvnc Ultravnc Viewer, classified under Out-of-bounds Write. CVSS score: 6.5/10. Published 2026-03-22.

How severe is CVE-2019-25600?

Medium severity. CVSS v3 base score is 6.5 out of 10.

Buffer overflow in Uvnc Ultravnc Viewer

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 repeate…

Vulnerability class: Buffer Overflow

EPSS: 0.000 (14.3th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H.

Affected products

Uvnc Ultravnc Viewer — versions 1.2.2.4

Weakness classification (CWE)

CWE-787 — Out-of-bounds Write

References

ExploitDB-46702 (exploit)
Official Product Homepage (product)
Product Reference (product)
VulnCheck Advisory: UltraVNC Viewer 1.2.2.4 Denial of Service via Buffer Overflow (third-party-advisory)

Frequently asked questions

What is CVE-2019-25600?: CVE-2019-25600 is a medium-severity vulnerability in Uvnc Ultravnc Viewer, classified under Out-of-bounds Write. CVSS score: 6.5/10. Published 2026-03-22.
How severe is CVE-2019-25600?: Medium severity. CVSS v3 base score is 6.5 out of 10.