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TI-2026-03276 Aliases CVE-2026-3787GHSA-97cv-xr93-496p

UltraVNC Windows Service cryptbase.dll uncontrolled search path

Priority LOW 33CWE-426Published · Updated

Key facts

Attack vector
Local
Privileges required
Low
User interaction
None
Attack complexity
High
Attack requirements
None
Impact type
Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
No fix listed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-426.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00184 8th percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
—UltraVNC1.6.4.0—No fix listedCNA
  • UltraVNC Vendor— Affected 1.6.4.0 Fixed in — No fix listed CNA

CPE configurations NVD · 2

CPEVersionsRoleVendor
cpe:2.3:a:uvnc:ultravnc:1.6.4.0:*:*:*:*:*:*:*1.6.4.0Vulnerableuvnc
cpe:2.3:o:microsoft:windows:-:*:*:*:*:*:*:*not specified by NVDRunning onMicrosoft
  • cpe:2.3:a:uvnc:ultravnc:1.6.4.0:*:*:*:*:*:*:* Versions 1.6.4.0 Vulnerable ·uvnc
  • cpe:2.3:o:microsoft:windows:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Microsoft

Remediation

No fixed version listed by the sources yet.

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-3787
  2. 2026-10-03 Alias added: GHSA-97cv-xr93-496p

References

Other 1

  • TI-2020-19268 UltraVNC Launcher 1.2.4.0 - 'RepeaterHost' Denial of Service CVSS 4.0MEDIUM 6.7
  • TI-2026-04323 UltraVNC Service version.dll uncontrolled search path CVSS 4.0HIGH 7.3
  • TI-2020-19267 UltraVNC Launcher 1.2.4.0 - 'Password' Denial of Service CVSS 4.0MEDIUM 6.7
  • TI-2026-06899 UltraVNC repeater HTTP server global buffer overflow via long URI (pre-auth RCE) CVSS 4.0CRITICAL 9.3
  • TI-2019-05946 Heap-based buffer overflow in Kaspersky Lab UltraVNC CVSS 3.1CRITICAL 9.8
  • TI-2019-05945 Heap-based buffer overflow in Kaspersky Lab UltraVNC CVSS 3.1CRITICAL 9.8
See all 36 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences