CVE-2019-25600: UltraVNC Viewer 1.2.2.4 Denial of Service via Buffer Overflow

Published Mar 22, 2026
·
Updated

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.

Affected Software

1 affected component
UltraVNC UltraVNC Viewer=1.2.2.4

Event History

Mar 22, 2026
CVE Published
via MITRE·01:38 PM
Data Sourced
via MITRE·01:38 PM
DescriptionSeverityWeakness
Data Sourced
via NVD·02:16 PM
DescriptionSeverityWeakness
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Frequently Asked Questions

1

What is the severity of CVE-2019-25600?

CVE-2019-25600 has a severity rating of medium due to its denial of service potential.

2

How do I fix CVE-2019-25600?

To fix CVE-2019-25600, upgrade UltraVNC Viewer to a version that is not vulnerable as specified by the vendor.

3

What type of vulnerability is CVE-2019-25600?

CVE-2019-25600 is a denial of service vulnerability caused by a buffer overflow.

4

What is affected by CVE-2019-25600?

CVE-2019-25600 affects UltraVNC Viewer version 1.2.2.4.

5

How can an attacker exploit CVE-2019-25600?

An attacker can exploit CVE-2019-25600 by supplying an oversized string to the VNC Server input field to crash the application.

Contact

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