Description
UltraVNC Viewer 1.2.4.0 contains a denial of service vulnerability that allows attackers to crash the application by manipulating VNC Server input. Attackers can generate a malformed 256-byte payload and paste it into the VNC Server connection dialog to trigger an application crash.
Published: 2026-02-05
Score: 4.6 Medium
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories

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History

Thu, 05 Mar 2026 02:15:00 +0000

Type Values Removed Values Added
First Time appeared Ultravnc vnc Viewer
CPEs cpe:2.3:a:ultravnc:vnc_viewer:1.2.4.0:*:*:*:*:*:*:*
Vendors & Products Ultravnc vnc Viewer

Fri, 06 Feb 2026 12:15:00 +0000

Type Values Removed Values Added
First Time appeared Ultravnc
Ultravnc ultravnc
Vendors & Products Ultravnc
Ultravnc ultravnc

Thu, 05 Feb 2026 19:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Thu, 05 Feb 2026 16:30:00 +0000

Type Values Removed Values Added
Description UltraVNC Viewer 1.2.4.0 contains a denial of service vulnerability that allows attackers to crash the application by manipulating VNC Server input. Attackers can generate a malformed 256-byte payload and paste it into the VNC Server connection dialog to trigger an application crash.
Title UltraVNC Viewer 1.2.4.0 - 'VNCServer' Denial of Service
Weaknesses CWE-770
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

cvssV4_0

{'score': 4.6, 'vector': 'CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N'}


Subscriptions

Ultravnc Ultravnc Vnc Viewer
cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-03-05T01:28:08.821Z

Reserved: 2026-02-03T16:27:45.306Z

Link: CVE-2020-37134

cve-icon Vulnrichment

Updated: 2026-02-05T18:43:09.456Z

cve-icon NVD

Status : Deferred

Published: 2026-02-05T17:16:08.690

Modified: 2026-04-15T00:35:42.020

Link: CVE-2020-37134

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-02-06T12:05:23Z

Weaknesses