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Vulnerability record · CVE-2020-37133 · published 5 February 2026

CVE-2020-37133: Uvnc ultravnc stack-based buffer overflow vulnerability

Uvnc · 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.

6.7 CVSS 4.0 Medium EPSS 0.55% · top 56.0% CWE-121 · Stack-based buffer overflowCWE-787 · Out-of-bounds write
6.7CVSS 4.0 base score
0.55%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
3References, 1 tagged exploit
17 Jun 2026Last modified by NVD

Description

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.

CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://www.exploit-db.com/exploits/48288 ExploitThird Party AdvisoryVDB Entry
https://www.uvnc.com/ Product
https://www.vulncheck.com/advisories/ultravnc-launcher-repeaterhost-denial-of-service Third Party Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

9.8CVE-2019-8266Uvnc ultravnc out-of-bounds read vulnerabilityUltraVNC revision 1207 has multiple out-of-bounds access vulnerabilities connected with improper usage of ClientConnection::Copybuffer function in VN…EPSS 2.8%9.8CVE-2019-8271Uvnc ultravnc heap-based buffer overflow vulnerabilityUltraVNC revision 1211 has a heap buffer overflow vulnerability in VNC server code inside file transfer handler, which can potentially result code ex…EPSS 8.3%9.8CVE-2019-8264Uvnc ultravnc out-of-bounds read vulnerabilityUltraVNC revision 1203 has out-of-bounds access vulnerability in VNC client inside Ultra2 decoder, which can potentially result in code execution. Th…EPSS 3.1%9.8CVE-2019-8274Uvnc ultravnc heap-based buffer overflow vulnerabilityUltraVNC revision 1211 has a heap buffer overflow vulnerability in VNC server code inside file transfer offer handler, which can potentially in resul…EPSS 8.3%9.8CVE-2019-8272Uvnc ultravnc vulnerabilityUltraVNC revision 1211 has multiple off-by-one vulnerabilities in VNC server code, which can potentially result in code execution. This attack appear…EPSS 3.9%9.8CVE-2019-8265Uvnc ultravnc out-of-bounds read vulnerabilityUltraVNC revision 1207 has multiple out-of-bounds access vulnerabilities connected with improper usage of SETPIXELS macro in VNC client code, which c…EPSS 3.1%9.8CVE-2019-8275Uvnc ultravnc vulnerabilityUltraVNC revision 1211 has multiple improper null termination vulnerabilities in VNC server code, which result in out-of-bound data being accessed by…EPSS 4.0%9.8CVE-2019-8268Uvnc ultravnc vulnerabilityUltraVNC revision 1206 has multiple off-by-one vulnerabilities in VNC client code connected with improper usage of ClientConnection::ReadString funct…EPSS 3.9%

Source: NIST National Vulnerability Database (record CVE-2020-37133), CISA KEV, FIRST EPSS (scores of 2026-10-07). This page is refreshed as NVD updates the record.