Vulnerability in Microsoft Windows
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.0 (High). Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.002 (6.5th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 6th percentile — 6.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: +0.000
Affected products
- Microsoft Windows
- Uvnc Ultravnc — versions 1.6.4.0
- Ultravnc — versions 1.6.4.0
Weakness classification (CWE)
References
- vuldb.com/ (VDB Entry, Third Party Advisory, vdb-entry)
- vuldb.com/ (signature, Permissions Required, permissions-required, VDB Entry)
- vuldb.com/ (VDB Entry, Third Party Advisory, third-party-advisory)
- drive.google.com/file/d/14ixv_1i4D2VrZWyl4RKsvFcN1AMF_qNx/view (Permissions Required, related)
Frequently asked questions
- What is CVE-2026-3787?
- CVE-2026-3787 is a high-severity vulnerability in Microsoft Windows, classified under Untrusted Search Path. CVSS score: 7.0/10. Published 2026-03-08.
- How severe is CVE-2026-3787?
- High severity. CVSS v3 base score is 7.0 out of 10.