---
id: CVE-2026-116723
title: FLTK through 1.4.5 Stack Buffer Overflow via Fl_BMP_Image colors_used Field
summary: >-
  FLTK through 1.4.5 contains a stack-based buffer overflow vulnerability in
  Fl_BMP_Image::load_bmp_() that allows attackers to corrupt stack memory by
  supplying an oversized BMP colors_used field. Attackers can craft BMP or ICO
  files with…
severity: high
cvss: 7.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H'
cvssSource: cna
cwe:
  - CWE-121
vendor: fltk
product: fltk
affected:
  - fltk <= 1.4.5
published: '2026-10-26'
updated: '2026-10-26'
sourceUpdated: '2026-10-26T21:52:27.469Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-116723'
references:
  - url: 'https://github.com/fltk/fltk/issues/1632'
    label: 'GitHub Issue #1632'
  - url: 'https://github.com/fltk/fltk'
  - url: >-
      https://github.com/fltk/fltk/commit/3a049d8262dc759cf9737339420e8457e24c0cb1
  - url: >-
      https://github.com/fltk/fltk/blob/release-1.4.5/src/Fl_BMP_Image.cxx#L255-L265
  - url: 'https://hackmd.io/@haindpwn/fltk-bmp-image-stack-heap-overflow'
  - url: >-
      https://www.vulncheck.com/advisories/fltk-through-1.4.5-stack-buffer-overflow-via-fl-bmp-image-colors-used-field
    label: >-
      VulnCheck Advisory: FLTK through 1.4.5 Stack Buffer Overflow via
      Fl_BMP_Image colors_used Field
tags:
  - cve.org
epss: 0.0016
epssPercentile: 0.05062
ingestedAt: '2026-10-27T16:11:59.119Z'
---

## Overview

FLTK through 1.4.5 contains a stack-based buffer overflow vulnerability in Fl_BMP_Image::load_bmp_() that allows attackers to corrupt stack memory by supplying an oversized BMP colors_used field. Attackers can craft BMP or ICO files with colors_used above 256 to overflow the 768-byte colormap array, causing crashes or potential code execution.

## Affected

- `fltk <= 1.4.5`

## Remediation

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