Is CVE-2019-25600 actively exploited?

No active exploitation of CVE-2019-25600 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2019-25600 be exploited remotely?

Yes. CVE-2019-25600 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2019-25600?

CVE-2019-25600 has a CVSS score of 6.5 (MEDIUM).

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MEDIUM

CVE-2019-25600

CWE-787Published: March 22, 2026· Updated: Mar 23, 2026

6.5

CVSS v3.1

EPSS:0.03%probability of exploitation in 30 daysPercentile:9.5th

Official 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.

NVD Source

Technical Analysis

CVE-2019-25600 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

Exploitation does not require any privileges, though user interaction (Required) is needed, which slightly reduces the risk of mass automated attacks.

A successful exploit results in availability disruption (denial of service), with a CVSS base score of 6.5.

From a weakness classification perspective (CWE-787): Out-of-bounds write vulnerabilities can lead to data corruption, crashes, or arbitrary code execution.