---
id: CVE-2026-125250
title: FFmpeg through 9.0.2 GIF Encoder Heap Buffer Overflow via shrunk_buf Remap
summary: >-
  FFmpeg through 9.0.2 contains a heap buffer overflow in the GIF encoder's
  gif_image_write_image() in libavcodec/gif.c because shrunk_buf is sized from
  the first frame's linesize. Attackers can supply PAL8 video whose frame
  linesize grows…
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-122
vendor: FFmpeg
product: FFmpeg
affected:
  - FFmpeg <= 9.0.2
published: '2026-11-09'
updated: '2026-11-09'
sourceUpdated: '2026-11-09T19:11:56.203Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-125250'
references:
  - url: 'https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/25690'
  - url: >-
      https://github.com/FFmpeg/FFmpeg/commit/26c2980980295e5516f308c5a2792d2a72e43eae
    label: Patch Commit
  - url: 'https://github.com/FFmpeg/FFmpeg/blob/n9.0.2/libavcodec/gif.c#L405'
  - url: 'https://github.com/FFmpeg/FFmpeg'
  - url: >-
      https://www.vulncheck.com/advisories/ffmpeg-through-9.0.2-gif-encoder-heap-buffer-overflow-via-shrunk-buf-remap
    label: >-
      VulnCheck Advisory: FFmpeg through 9.0.2 GIF Encoder Heap Buffer Overflow
      via shrunk_buf Remap
tags:
  - cve.org
ingestedAt: '2026-11-09T19:18:02.575Z'
---

## Overview

FFmpeg through 9.0.2 contains a heap buffer overflow in the GIF encoder's gif_image_write_image() in libavcodec/gif.c because shrunk_buf is sized from the first frame's linesize. Attackers can supply PAL8 video whose frame linesize grows mid-stream, causing remap_frame_to_palette() to write past shrunk_buf and corrupt the heap during GIF transcoding.

## Affected

- `FFmpeg <= 9.0.2`

## Remediation

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