CVE-2026-3787

Name: CVE-2026-3787
Creator: NVD / NIST
Published: 2026-03-08T23:15:50.69+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.4/10EPSS 0.17%

Last modified Jun 17, 2026

CVE-2026-3787 is a medium-severity vulnerability rated 6.4/10 on the CVSS scale. 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. EPSS estimates a 0.17% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

7/10

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

CVSS 4.0

6.4/10

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

EPSS Probability

0.17%

6.1th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Uvnc	Ultravnc	1.6.4.0

References

https://drive.google.com/file/d/14ixv_1i4D2VrZWyl4RKsvFcN1AMF_qNx/viewPermissions Required
https://vuldb.com/?ctiid.349754Permissions Required, VDB Entry
https://vuldb.com/?id.349754Third Party Advisory, VDB Entry
https://vuldb.com/?submit.767257Third Party Advisory, VDB Entry

Timeline

Published: Mar 8, 2026
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-3787?

How severe is CVE-2026-3787?

CVE-2026-3787 has a CVSS score of 6.4/10 (MEDIUM severity). The EPSS model estimates a 0.17% probability of exploitation in the next 30 days.

How do I fix CVE-2026-3787?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-3787?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST