Ultravnc
CVE-2026-3787
MEDIUM
Severity by source
CVSS:4.0/AV:L/AC:H/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P/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:X/V:X/RE:X/U:X
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
Lifecycle Timeline
4DescriptionCVE.org
A weakness has been identified in UltraVNC 1.6.4.0 on Windows. This affects an unknown function in the library cryptbase.dll of the component Windows Service. This manipulation causes uncontrolled search path. The attack requires local access. A high degree of complexity is needed for the attack. The exploitability is reported as difficult. The vendor was contacted early about this disclosure but did not respond in any way.
AnalysisAI
UltraVNC 1.6.4.0 on Windows contains an uncontrolled search path vulnerability in cryptbase.dll that allows local authenticated attackers with low privileges to achieve arbitrary code execution through DLL hijacking. Successful exploitation requires local access and considerable technical complexity, though the vendor has not provided a patch despite early disclosure notification. This vulnerability carries a high impact rating with potential for complete system compromise (confidentiality, integrity, and availability).
Technical ContextAI
Classified as CWE-426 (Untrusted Search Path). Affects the library cryptbase.dll of the component of Ultravnc. A weakness has been identified in UltraVNC 1.6.4.0 on Windows. This affects an unknown function in the library cryptbase.dll of the component Windows Service. This manipulation causes uncontrolled search path. The attack requires local access. A high degree of complexity is needed for the attack. The exploitability is reported as difficult. The vendor was contacted early about this disclosure but did not respond in any way.
RemediationAI
Monitor vendor advisories for a patch.
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Same weakness CWE-426 – Untrusted Search Path
View allSame technique Information Disclosure
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External POC / Exploit Code
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