---
title: "CVE-2026-116723: FLTK - Buffer Overflow"
description: "FLTK through 1.4.5 contains a stack-based buffer overflow caused by an oversized BMP colors_used field in Fl_BMP_Image::load_bmp_(), letting attackers cause crashes or execute code by crafting malicious BMP or ICO files, exploit requires processing crafted image files."
url: https://panop.io/threat-heartbeat/CVE-2026-116723/
---

# CVE-2026-116723 FLTK - Buffer Overflow

FLTK through 1.4.5 contains a stack-based buffer overflow caused by an oversized BMP colors\_used field in Fl\_BMP\_Image::load\_bmp\_(), letting attackers cause crashes or execute code by crafting malicious BMP or ICO files, exploit requires processing crafted image files.

CVSS base score 7.8 /10

High

CISA KEV

Not listed

Public exploit

None known

Authentication

Not required

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-116723)

## Details

Type

Buffer Overflow

Impact

Remote Code Execution, Denial Of Service

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Published

26 October 2026

Updated

27 October 2026

Weakness

[CWE-121](https://cwe.mitre.org/data/definitions/121.html)

## Vendor fix

Update to a version later than 1.4.5 or apply available patches.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

## References

- [https://nvd.nist.gov/vuln/detail/CVE-2026-116723](https://nvd.nist.gov/vuln/detail/CVE-2026-116723)
- [https://github.com/fltk/fltk/blob/release-1.4.5/src/Fl\_BMP\_Image.cxx#L255-L265](https://github.com/fltk/fltk/blob/release-1.4.5/src/Fl_BMP_Image.cxx#L255-L265)
- [https://github.com/fltk/fltk/commit/3a049d8262dc759cf9737339420e8457e24c0cb1](https://github.com/fltk/fltk/commit/3a049d8262dc759cf9737339420e8457e24c0cb1)
- [https://github.com/fltk/fltk/issues/1632](https://github.com/fltk/fltk/issues/1632)
- [https://hackmd.io/@haindpwn/fltk-bmp-image-stack-heap-overflow](https://hackmd.io/@haindpwn/fltk-bmp-image-stack-heap-overflow)
- [https://www.vulncheck.com/advisories/fltk-through-1.4.5-stack-buffer-overflow-via-fl-bmp-image-colors-used-field](https://www.vulncheck.com/advisories/fltk-through-1.4.5-stack-buffer-overflow-via-fl-bmp-image-colors-used-field)
- [https://github.com/fltk/fltk](https://github.com/fltk/fltk)

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## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

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