High · CVSS 7.8CVE-2026-107615

DLL search order hijacking via screenhooks libraries in TightVNC ServerCVE-2026-107615

Answer in brief

CVE-2026-107615 records a High severity (CVSS 7.8) vulnerability in DLL search order hijacking via screenhooks libraries in TightVNC Server. The current sources do not mark it as known exploited. The current feed maps GlavSoft/TightVNC (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Oct 8, 2026Updated Oct 8, 2026Source checked Oct 8, 2026First seen by HOL Oct 8, 2026Material review Oct 8, 2026

Upstream Advisory

Key facts

Risk: High · CVSS 7.8
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

CVSS is 7.8. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps GlavSoft/TightVNC (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
GlavSoft/TightVNCgeneric	>=0 <2.8.88	2.8.88

Recommended response

Check inventory. Check lockfiles and deployed manifests for GlavSoft/TightVNC.
Review the reported fix. Source-reported solution: Upgrade TightVNC for Windows to version 2.8.88 or later.

Evidence timeline and material changes

Published upstream
Oct 8, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Oct 8, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Oct 8, 2026

Sources and claim methodology

Upstream source 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).

Quoted source text, attributed separately from HOL analysis.