What is the CVSS score of CVE-2020-37134?

CVE-2020-37134 has a CVSS 3.1 base score of 7.5 (High). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. EPSS exploitation probability: 0.0%.

Is there a public PoC exploit available for CVE-2020-37134?

Yes, a public proof-of-concept exploit is available for CVE-2020-37134. Prioritise patching immediately. EPSS: 0.0%.

How to fix or mitigate CVE-2020-37134?

Within 24 hours: Identify and inventory all systems running UltraVNC Viewer 1.2.4.0 across the organization. Within 7 days: Restrict VNC usage to trusted internal networks only and disable remote VNC connections from untrusted sources; monitor for suspicious connection attempts. Within 30 days: Migrate to an alternative remote access solution or evaluate UltraVNC successor versions once patches become available; document all affected systems and their replacement timeline.

CVE-2020-37134

HIGH

Allocation of Resources Without Limits or Throttling (CWE-770)

2026-02-05 disclosure@vulncheck.com

Denial Of Service

7.5

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

7.5 HIGH

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

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Lifecycle Timeline

Analysis Generated

Mar 12, 2026 - 21:55 vuln.today

PoC Detected

Feb 05, 2026 - 20:47 vuln.today

Public exploit code

CVE Published

Feb 05, 2026 - 17:16 nvd

HIGH 7.5

DescriptionCVE.org

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.

AnalysisAI

Technical ContextAI

This vulnerability (CWE-770: Allocation of Resources Without Limits or Throttling) 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.

Affected ProductsAI

UltraVNC Viewer 1.2.4.0 contains a denial of service vulnerability that

RemediationAI

Monitor vendor advisories for a patch. Restrict network access to the affected service where possible.

CVE-2020-37134 vulnerability details – vuln.today

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CVE-2020-37134

Severity by source

CVSS VectorNVD

Lifecycle Timeline

DescriptionCVE.org

AnalysisAI

Technical ContextAI

Affected ProductsAI

RemediationAI

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External POC / Exploit Code