Home/CVE/UltraVNC Launcher 1.2.4.0 contains a denial of service vulnerability in the Repeater Host configuration field that allow
CVE

CVE-2020-37133

UltraVNC Launcher 1.2.4.0 contains a denial of service vulnerability in the Repeater Host configuration field that allow

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.

HIGH · CVSS 7.5 EPSS 0.00015
Act now
  • Public exploit or PoC is available
  • SSVC automatable: yes - attacks can be scripted at scale
  • CVSS base score ≥ 7.0
Sigma rules2 YARA rules0
⬡

Weakness Classification

CWE-121Stack-based Buffer Overflow
CWE-787Out-of-bounds Write
▤

Affected Products & Versions

1
uvnc ultravnc<= 1.2.4.0
⚠

Public Exploits & PoCs

1
pocwww.exploit-db.com · 48288www.exploit-db.com
◈

Sigma Hunt Rules

2
Exact rules name this CVE ID. Product rules name an affected product in their title. Related rules cover techniques used by actors who exploited this CVE. Showing the most relevant matches; the complete related set is on the full drill-down.
producthighSuspicious UltraVNC Execution
productmediumUse of UltraVNC Remote Access Software
▣

Scoring & Timeline

7.5
HIGH · CVSS v3.1 · disclosure@vulncheck.com
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD05 Feb 2026 · 05:16 PM
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
SSVC triage · cisa-vulnrichment
Exploitation
poc
Automatable
yes
Technical impact
partial
SSVC asks the questions that actually drive patch urgency: is it being exploited, can attacks be automated, and how total is the impact.
🔗

References & Sources

2
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://www.uvnc.com/Product
https://www.vulncheck.com/advisories/ultravnc-launcher-repeaterhost-denial-of-serviceThird Party Advisory
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