---
id: CVE-2026-125259
title: FFmpeg through 9.0.2 Heap Buffer Overflow via ProRes prores_ks Encoder
summary: >-
  FFmpeg through 9.0.2 contains an integer overflow vulnerability in
  ff_prores_kostya_encode_init() that miscalculates frame_size_upper_bound using
  32-bit arithmetic for large frame dimensions. Attackers can supply a
  high-resolution video …
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-190
vendor: FFmpeg
product: FFmpeg
affected:
  - FFmpeg <= 9.0.2
published: '2026-11-09'
updated: '2026-11-09'
sourceUpdated: '2026-11-09T19:12:02.579Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-125259'
references:
  - url: 'https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/25573'
  - url: >-
      https://github.com/FFmpeg/FFmpeg/commit/439b452f9fe916a9f7d8788ab6afee8fac846b0b
    label: Patch Commit
  - url: >-
      https://github.com/FFmpeg/FFmpeg/blob/n9.0.2/libavcodec/proresenc_kostya_common.c#L286
  - url: 'https://github.com/FFmpeg/FFmpeg'
  - url: >-
      https://www.vulncheck.com/advisories/ffmpeg-through-9.0.2-heap-buffer-overflow-via-prores-prores-ks-encoder
    label: >-
      VulnCheck Advisory: FFmpeg through 9.0.2 Heap Buffer Overflow via ProRes
      prores_ks Encoder
tags:
  - cve.org
ingestedAt: '2026-11-09T20:27:27.082Z'
---

## Overview

FFmpeg through 9.0.2 contains an integer overflow vulnerability in ff_prores_kostya_encode_init() that miscalculates frame_size_upper_bound using 32-bit arithmetic for large frame dimensions. Attackers can supply a high-resolution video transcoded with the prores_ks encoder, causing encode_frame() to write slices past an undersized packet buffer and corrupt heap memory.

## Affected

- `FFmpeg <= 9.0.2`

## Remediation

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