Vulnerability · Published Mar 8, 2026 · Assigned by VulDB

CVE-2026-3787UltraVNC Windows Service cryptbase.dll uncontrolled search path

High 7.0

In plain English

A high-severity uncontrolled search path in UltraVNC. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 8% of all known vulnerabilities).

Severity (CVSS 3.1)7.0High

Exploit odds (30 days)0.2%top 91.9% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

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.

Affected products (as reported)

Vendor	Product	Versions
n/a	UltraVNC	1.6.4.0

Weakness: CWE-427, CWE-426 · Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:X/RC:R

References

VDB-349754 | UltraVNC Windows Service cryptbase.dll uncontrolled search path vdb-entry
VDB-349754 | CTI Indicators (IOB, IOC, TTP, IOA) signature, permissions-required
Submit #767257 | UltraVNC 1.6.4.0 Uncontrolled Search Path third-party-advisory
https://drive.google.com/file/d/14ixv_1i4D2VrZWyl4RKsvFcN1AMF_qNx/view related