---
id: CVE-2026-107614
title: >-
  An integer underflow in WinCursorShapeUtils::trimTransparent() in GlavSoft
  TightVNC Server for Windows before 2.8.88 allows a local authenticated user to
  crash the server, and potentially read out-of-bounds memory, by causing a
  cursor sh…
summary: >-
  An integer underflow in WinCursorShapeUtils::trimTransparent() in GlavSoft
  TightVNC Server for Windows before 2.8.88 allows a local authenticated user to
  crash the server, and potentially read out-of-bounds memory, by causing a
  cursor sh…
severity: medium
cvss: 6.1
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:H'
cwe:
  - CWE-125
  - CWE-191
vendor: GlavSoft
product: TightVNC
affected:
  - TightVNC < 2.8.88
published: '2026-10-08'
updated: '2026-10-08'
sourceUpdated: '2026-10-08T21:10:00.133'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-107614'
references:
  - url: 'https://sourceforge.net/p/vnc-tight/bugs/1661/'
    label: 33c584b5-0579-4c06-b2a0-8d8329fcab9c
  - url: 'https://www.tightvnc.com/whatsnew.php'
    label: 33c584b5-0579-4c06-b2a0-8d8329fcab9c
tags:
  - nvd
  - cve.org
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-10-08T14:00:49.369592Z'
ingestedAt: '2026-10-08T14:47:16.341Z'
---

## Overview

An integer underflow in WinCursorShapeUtils::trimTransparent() in GlavSoft TightVNC Server for Windows before 2.8.88 allows a local authenticated user to crash the server, and potentially read out-of-bounds memory, by causing a cursor shape with a width or height of zero to be processed on the DXGI capture path. The loop bound width - 1 wraps to 0xFFFFFFFF, producing an access roughly 4 GB beyond the 64 KB cursor buffer; a monochrome cursor of height 1 also becomes 0 because getCursorHeight() halves the height in place.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.