CVE-2026-3787UltraVNC Windows Service cryptbase.dll uncontrolled search path
- 7.3HighCVSS base score
- 0.18%Exploitation in 30 daysEPSS · top 92% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
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.
Timeline
ID reserved
By VulDB
Published
- 2 days later
· 2 days later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| VulDBCNA (assigner) | 4.0 | High7.3 | 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 |
| VulDBCNA (assigner) | 3.1 | High7.0 | 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 |
| VulDBCNA (assigner) | 3.0 | High7.0 | CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:X/RC:R |
| VulDBCNA (assigner) | 2.0 | Medium6.0 | AV:L/AC:H/Au:S/C:C/I:C/A:C/E:POC/RL:ND/RC:UR |
| NVDNVD · Analyzed | 4.0 | Medium6.4 | 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 (exploitation in 30 days)
- 0.18% · top 92% of all CVEs (13 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: total
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.3.
Affected products
UltraVNC
- affected 1.6.4.0
References
References4
- VDB-349754 | UltraVNC Windows Service cryptbase.dll uncontrolled search path (opens in a new tab)vdb-entry
- VDB-349754 | CTI Indicators (IOB, IOC, TTP, IOA) (opens in a new tab)signaturepermissions-required
- Submit #767257 | UltraVNC 1.6.4.0 Uncontrolled Search Path (opens in a new tab)third-party-advisory
- https://drive.google.com/file/d/14ixv_1i4D2VrZWyl4RKsvFcN1AMF_qNx/view (opens in a new tab)related
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-10277 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-3787)Record last updated .