Vulnerability Report

CVE-2026-3787

Title: Uncontrolled Search Path in UltraVNC

Other

Proof Of Concept

No public PoC currently indexed for CVE-2026-3787.

CWE Category CWE-426

Published Date Mar 08, 2026

Modified Date Apr 29, 2026

Exploit Status Not Found

Score 6.4 CVSS v4.0

Exploit Probability (EPSS)

0.18%

Vulnerability Summary

CVE-2026-3787: 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.

Impacted Vendors

ultravnc 1

uvnc 1

Reference Links

https://drive.google.com/file/d/14ixv_1i4D2VrZWyl4RKsvFcN1AMF_qNx/view https://vuldb.com/?ctiid.349754 https://vuldb.com/?id.349754 https://vuldb.com/?submit.767257

CVSS v4.0

Source Entity [email protected]

Severity MEDIUM

6.4

Attack Vector

LOCAL

Complexity

HIGH

Privileges

N/A

Interaction

NONE

Confidentiality

N/A

Integrity

N/A

Availability

N/A

Scope

N/A

RAW VECTOR

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

CVSS v3.1

Source Entity [email protected]

Severity HIGH

7.0

Attack Vector

LOCAL

Complexity

HIGH

Privileges

N/A

Interaction

NONE

Confidentiality

N/A

Integrity

N/A

Availability

N/A

Scope

UNCHANGED

RAW VECTOR CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS v2.0

Source Entity [email protected]

Severity MEDIUM

6.0

Access Vector

N/A

Authentication

N/A

RAW VECTOR AV:L/AC:H/Au:S/C:C/I:C/A:C

Associated Attack Patterns (CAPEC)

Total: Patterns