Is CVE-2026-3787 in the CISA KEV catalog?

No. CVE-2026-3787 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-3787?

CVE-2026-3787 has a CVSS v3 base score of 7.0 (HIGH).

What is the EPSS score for CVE-2026-3787?

CVE-2026-3787 has an EPSS score of 0.17% (6th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix or mitigate CVE-2026-3787?

No published fix for CVE-2026-3787 has been found yet. Check the linked vendor advisories for guidance as it becomes available.

CVE & CISA-KEV Catalog

CVE-2026-3787

HIGH

7.0

CVSS v3

NVD

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.

CWE-426 CWE-427

How to fix

No published remediation has been found for this vulnerability's affected products yet.

Mitigation guidance may be in the linked vendor advisories in the References section below.

CVSS v3 Vector

Exploitability

Attack VectorLocal

Attack ComplexityHigh

Privileges RequiredLow

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

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

Exploit Intelligence

0.17%probability of exploitation in 30 days

6thpercentile

Low risk: more likely to be exploited than 6% of all known CVEs.

References

Third-Party Advisory2

VDB Entry1

vuldb.com

Other references1

drive.google.com

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-04-29.