---
id: CVE-2026-110601
title: >-
  libsixel before 1.8.7-r1 and 1.9.0 through 1.10.5 contains a heap
  out-of-bounds write vulnerability in gif_init_frame() in src/fromgif.c, which
  never checks the GIF transparent color index against the palette size
summary: >-
  libsixel before 1.8.7-r1 and 1.9.0 through 1.10.5 contains a heap
  out-of-bounds write vulnerability in gif_init_frame() in src/fromgif.c, which
  never checks the GIF transparent color index against the palette size.
  Attackers can supply a…
severity: medium
cvss: 6.3
cvssVector: 'CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:H'
cwe:
  - CWE-787
published: '2026-10-14'
updated: '2026-10-14'
sourceUpdated: '2026-10-14T15:17:11.530'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-110601'
references:
  - url: 'https://github.com/libsixel/libsixel/blob/v1.10.5/src/fromgif.c#L219-L240'
    label: disclosure@vulncheck.com
  - url: 'https://github.com/saitoha/libsixel/blob/v1.8.7/src/fromgif.c#L182-L248'
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/saitoha/libsixel/commit/bdbab09816eb9188429c37a50b97c5e66dfe5047
    label: disclosure@vulncheck.com
  - url: 'https://github.com/saitoha/libsixel/issues/220'
    label: disclosure@vulncheck.com
  - url: 'https://github.com/saitoha/libsixel/releases/tag/v1.8.7-r1'
    label: disclosure@vulncheck.com
  - url: 'https://hackmd.io/@haind-pwn/libsixel-gif-transparent-index-oob-write'
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/libsixel-before-1.8.7-r1-and-1.9.0-through-1.10.5-heap-out-of-bounds-write-via-gif
    label: disclosure@vulncheck.com
tags:
  - nvd
ingestedAt: '2026-10-14T15:36:14.002Z'
---

## Overview

libsixel before 1.8.7-r1 and 1.9.0 through 1.10.5 contains a heap out-of-bounds write vulnerability in gif_init_frame() in src/fromgif.c, which never checks the GIF transparent color index against the palette size. Attackers can supply a crafted GIF with a small color table and large transparent index, processed with a background color set, to write bytes past the palette buffer, causing heap corruption or crashes.

## Remediation

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