CVE-2026-107615

DLL search order hijacking via screenhooks libraries in TightVNC Server

Published Oct 8, 2026 CVSS 3.1 · 7.8 High EPSS < 1% KEV · Not listed
Description
An uncontrolled search path element vulnerability in GlavSoft TightVNC Server for Windows before 2.8.88 allows a local authenticated user to execute arbitrary code with SYSTEM privileges. DynamicLibrary::init() (and ThemeLib) load screenhooks32.dll / screenhooks64.dll with LoadLibrary() using a bare file name and no LOAD_LIBRARY_SEARCH_* flags, so the TightVNC service follows the default DLL search order and loads an attacker-planted DLL from a writable directory earlier in that order (for example, an installation directory with permissive ACLs).

Remediation

Vendor Solution

Upgrade TightVNC for Windows to version 2.8.88 or later.


Vendor Workaround

Ensure the TightVNC installation directory and every directory on the system PATH are writable only by administrators.

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
First Time appeared Glavsoft
Glavsoft tightvnc
Vendors & Products Glavsoft
Glavsoft tightvnc
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description An uncontrolled search path element vulnerability in GlavSoft TightVNC Server for Windows before 2.8.88 allows a local authenticated user to execute arbitrary code with SYSTEM privileges. DynamicLibrary::init() (and ThemeLib) load screenhooks32.dll / screenhooks64.dll with LoadLibrary() using a bare file name and no LOAD_LIBRARY_SEARCH_* flags, so the TightVNC service follows the default DLL search order and loads an attacker-planted DLL from a writable directory earlier in that order (for example, an installation directory with permissive ACLs).
Title DLL search order hijacking via screenhooks libraries in TightVNC Server
Weaknesses CWE-427
References
Metrics cvssV3_1

{'score': 7.8, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
securin
Published
Updated
Oct 8, 2026, 2:00 PM
Reserved
Oct 8, 2026, 1:23 PM
Status
Awaiting Analysis
Published
Oct 8, 2026, 2:16 PM
Modified
Oct 8, 2026, 9:10 PM