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TI-2026-69579 Aliases CVE-2026-107612GHSA-95xq-4x4f-23hr

Incorrect permissions on TightVNC IPC shared memory in TightVNC Server

Priority LOW 35CWE-338Published · Updated

Key facts

Attack vector
Local
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
High · High · High
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA.

Summary

GlavSoft TightVNC Server for Windows before 2.8.88 assigns incorrect permissions to a shared memory segment used for inter-process communication. The segment is created with a NULL DACL and a predictable name derived from a time-seeded random number generator (CWE-338, CWE-732). A local authenticated user with low privileges can open the segment and read or overwrite the handles used between the TightVNC service and its desktop server process, which runs as SYSTEM. This could lead to disclosure of session data, privilege escalation, or denial of service.

Written with Claude Haiku 5.5 from the sources below · 2026-10-29

Description from the CNA

Incorrect permission assignment in GlavSoft TightVNC Server for Windows before 2.8.88 allows a local authenticated user to read or overwrite the inter-process communication handles used between the TightVNC service and its desktop server process. The named shared memory segment in the Global\ namespace that carries the pipe HANDLE values is created with a NULL DACL, and its name is derived from a time-seeded srand(time(0)) value that is predictable to one-second granularity. A low-privileged local process can open the mapping and tamper with the IPC channel of a service running as SYSTEM, potentially leading to disclosure of session data, privilege escalation, or denial of service.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00104 1st percentileScored 2026-11-07
Fix Fixed TightVNC (GlavSoft): 2.8.88

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
GlavSoftTightVNCbefore 2.8.882.8.88Patch availableCNA
  • TightVNC VendorGlavSoft Affected before 2.8.88 Fixed in 2.8.88 Patch available CNA

Remediation

Update TightVNC Server for Windows to version 2.8.88 or later, which fixes the flaw.

Written with Claude Haiku 5.5 from the sources below · 2026-10-29

  • Fix · CNA TightVNC (GlavSoft) Fixed in 2.8.88

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

  • Release ·

    GlavSoft TightVNC 2.8.88

    5 records Highest priority Priority LOW 5 LOW

    Other records, highest priority first

    • TI-2026-69582 DLL search order hijacking via screenhooks libraries in TightVNC ServerPriority LOW 35
    • TI-2026-69578 Out-of-bounds read in TightVNC Viewer ZRLE palette decodingPriority LOW 31
    • TI-2026-69581 Integer underflow in TightVNC Server cursor shape trimmingPriority LOW 26
    Show all 5 records →

Timeline

  1. 2026-10-08 Threatist record created from CVE-2026-107612
  2. 2026-10-08 Alias added: GHSA-95xq-4x4f-23hr

References

Patch 1

Other 1

  • TI-2026-69582 DLL search order hijacking via screenhooks libraries in TightVNC Server CVSS 3.1HIGH 7.8
  • TI-2026-69578 Out-of-bounds read in TightVNC Viewer ZRLE palette decoding CVSS 3.1HIGH 7.1
  • TI-2026-69581 Integer underflow in TightVNC Server cursor shape trimming CVSS 3.1MEDIUM 6.1
  • TI-2026-69580 NULL pointer dereference in TightVNC Server Win8ScreenDriver crashes server CVSS 3.1MEDIUM 5.9

Sources

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