---
id: CVE-2026-125182
title: FFmpeg through 9.0.2 Out-of-Bounds Read via Cook Decoder js_subband_start
summary: >-
  FFmpeg through 9.0.2 contains an out-of-bounds read vulnerability in the Cook
  decoder joint_decode() function because cook_decode_init() does not check
  js_subband_start against subbands. Attackers can supply a crafted RealMedia
  file whos…
severity: low
cvss: 3.3
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N'
cvssSource: cna
cwe:
  - CWE-125
vendor: FFmpeg
product: FFmpeg
affected:
  - FFmpeg <= 9.0.2
published: '2026-11-09'
updated: '2026-11-09'
sourceUpdated: '2026-11-09T19:11:07.513Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-125182'
references:
  - url: 'https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/24763'
  - url: >-
      https://github.com/FFmpeg/FFmpeg/commit/7145d13201c9f9c5253f40295714faa4f4ada1a0
    label: Patch Commit
  - url: 'https://github.com/FFmpeg/FFmpeg/blob/n9.0.2/libavcodec/cook.c#L854'
  - url: 'https://github.com/FFmpeg/FFmpeg'
  - url: >-
      https://www.vulncheck.com/advisories/ffmpeg-through-9.0.2-out-of-bounds-read-via-cook-decoder-js-subband-start
    label: >-
      VulnCheck Advisory: FFmpeg through 9.0.2 Out-of-Bounds Read via Cook
      Decoder js_subband_start
tags:
  - cve.org
ingestedAt: '2026-11-09T19:18:02.619Z'
---

## Overview

FFmpeg through 9.0.2 contains an out-of-bounds read vulnerability in the Cook decoder joint_decode() function because cook_decode_init() does not check js_subband_start against subbands. Attackers can supply a crafted RealMedia file whose extradata causes reads past decode_buffer_0, leaking pointers and decoder state into decoded audio to help defeat ASLR.

## Affected

- `FFmpeg <= 9.0.2`

## Remediation

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