What is the CVSS score of CVE-2020-37133?

CVE-2020-37133 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:H/I:N/A:N. EPSS exploitation probability: 0.0%.

Which versions of Ultravnc are affected by CVE-2020-37133?

UltraVNC Launcher 1.2.4.0 is vulnerable to a denial of service attack that can crash the application when users input excessively long strings into the Repeater Host configuration field.

Is there a public PoC exploit available for CVE-2020-37133?

Yes, a public proof-of-concept exploit is available for CVE-2020-37133. Prioritise patching immediately. EPSS: 0.0%.

How to fix or mitigate CVE-2020-37133?

Within 24 hours: Audit your environment to identify all systems running UltraVNC Launcher 1.2.4.0 and restrict access to administrative configuration functions. Within 7 days: Implement user training on suspicious input requests and consider disabling the Repeater Host feature if not operationally critical. Within 30 days: Upgrade to the latest available version of UltraVNC once patched, or migrate to an alternative remote access solution with active security support.

Ultravnc CVE-2020-37133

HIGH

Stack-based Buffer Overflow (CWE-121)

2026-02-05 disclosure@vulncheck.com

Denial Of Service Ultravnc

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:H/I:N/A:N

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:H/I:N/A:N

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

None

Availability

None

Lifecycle Timeline

Analysis Generated

Mar 12, 2026 - 21:55 vuln.today

PoC Detected

Feb 09, 2026 - 22:09 vuln.today

Public exploit code

CVE Published

Feb 05, 2026 - 17:16 nvd

HIGH 7.5

DescriptionCVE.org

UltraVNC Launcher 1.2.4.0 contains a denial of service vulnerability in the Repeater Host configuration field that allows attackers to crash the application. Attackers can paste an overly long string of 300 characters into the Repeater Host property to trigger an application crash.

AnalysisAI

Technical ContextAI

Classified as CWE-121 (Stack-based Buffer Overflow). Affects Ultravnc. UltraVNC Launcher 1.2.4.0 contains a denial of service vulnerability in the Repeater Host configuration field that allows attackers to crash the application. Attackers can paste an overly long string of 300 characters into the Repeater Host property to trigger an application crash.

RemediationAI

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

CVE-2020-37133 vulnerability details – vuln.today

Back

Ultravnc CVE-2020-37133

Severity by source

CVSS VectorNVD

Lifecycle Timeline

DescriptionCVE.org

AnalysisAI

Technical ContextAI

RemediationAI

Share

External POC / Exploit Code