Ultravnc
CVE-2020-37132
MEDIUM
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A06:2021 - Vulnerable and Outdated Components
ASVS 5.0
V15 - Secure Coding and Architecture Stack buffer bounds checking
MITRE ATT&CK
1 technique across 1 tactic: Execution The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Impact | CVSS 6.2 (MEDIUM). Attack vector: Local. Complexity: Low. Privileges required: None. User interaction: None. Exploitable via local access. Public exploit/POC available. |
| Exploit ScenarioDerived | An attacker could exploit this vulnerability to crash the application. |
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Alert meAnalysisAIv1 – Mar 12, 2026
UltraVNC Launcher 1.2.4.0 contains a denial of service vulnerability in its password configuration properties that allows local attackers to crash the application. [CVSS 6.2 MEDIUM]
RemediationAI
Monitor vendor advisories for a patch.
Affects your stack
Find out whether the stacks and servers you run are on an affected version.
Checking this CVE against your own stacks and servers is part of the Basic plan and up.
Technical ContextAI · show details
Classified as CWE-121 (Stack-based Buffer Overflow). Affects Ultravnc. UltraVNC Launcher 1.2.4.0 contains a denial of service vulnerability in its password configuration properties that allows local attackers to crash the application. Attackers can paste an overly long 300-character string into the password field to trigger an application crash and prevent normal launcher functionality.
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- Exploit and PoC references, threat intelligence from 22 sources
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Severity by source
AV:L/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
Lifecycle Timeline
2DescriptionCVE.org
UltraVNC Launcher 1.2.4.0 contains a denial of service vulnerability in its password configuration properties that allows local attackers to crash the application. Attackers can paste an overly long 300-character string into the password field to trigger an application crash and prevent normal launcher functionality.
Executive ViewAI
Organizations using UltraVNC Launcher 1.2.4.0 should be aware of moderate risk from CVE-2020-37132, a stack-based buffer overflow vulnerability rated CVSS 6.2. Exploitation could cause memory corruption or application crashes. Proof-of-concept code is publicly available. Organizations should apply vendor updates when available and monitor for exploitation.
Apply vendor patch. If patching is delayed: enable ASLR/DEP, apply network segmentation.
Threat Intelligence Overview
NVD
CVE.org
EPSS
Exploit-DB
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Denial of Service attacks render applications or systems unavailable by overwhelming resources or triggering failure conditions.
Affected Products (CPE)CVE.org
UltraVNC Launcher 1.2.4.0 contains a denial of service vulnerability in the Repeater Host configuration field that allow
UltraVNC versions up to 1.6.4.0 suffer from an uncontrolled search path vulnerability in version.dll loaded by the Servi
UltraVNC revision 1203 has out-of-bounds access vulnerability in VNC client inside RAW decoder, which can potentially re
UltraVNC revision 1211 has multiple improper null termination vulnerabilities in VNC server code, which result in out-of
UltraVNC revision 1211 has a heap buffer overflow vulnerability in VNC server code inside file transfer offer handler, w
UltraVNC revision 1211 has a heap buffer overflow vulnerability in VNC server code inside file transfer request handler,
UltraVNC revision 1211 has multiple off-by-one vulnerabilities in VNC server code, which can potentially result in code
UltraVNC revision 1211 has a heap buffer overflow vulnerability in VNC server code inside file transfer handler, which c
UltraVNC revision 1206 has multiple off-by-one vulnerabilities in VNC client code connected with improper usage of Clien
UltraVNC revision 1207 has multiple out-of-bounds access vulnerabilities connected with improper usage of ClientConnecti
UltraVNC revision 1207 has multiple out-of-bounds access vulnerabilities connected with improper usage of SETPIXELS macr
UltraVNC revision 1203 has out-of-bounds access vulnerability in VNC client inside Ultra2 decoder, which can potentially
GitHub PoC