---
id: CVE-2026-125267
title: >-
  FFmpeg before 8.1.3 and 9.x before 9.0.2 Heap Out-of-Bounds Write via APAC
  Decoder
summary: >-
  FFmpeg before 8.1.3 and 9.x before 9.0.2 contains a heap out-of-bounds write
  vulnerability in the APAC decoder in libavcodec/apac.c caused by an unreset
  bitstream index. Attackers can supply a crafted APAC file whose growing
  bitstream_in…
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 < 8.1.3
  - FFmpeg >= 9.0 < 9.0.2
published: '2026-11-09'
updated: '2026-11-09'
sourceUpdated: '2026-11-09T19:12:08.200Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-125267'
references:
  - url: 'https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/24432'
  - url: >-
      https://github.com/FFmpeg/FFmpeg/commit/e15ddb7f9a2f9b3ab8ac305efb6f94ddc18463d0
    label: Patch Commit
  - url: 'https://github.com/FFmpeg/FFmpeg/blob/n9.0.1/libavcodec/apac.c#L146'
  - url: 'https://github.com/FFmpeg/FFmpeg'
  - url: >-
      https://www.vulncheck.com/advisories/ffmpeg-before-8.1.3-and-9-x-before-9.0.2-heap-out-of-bounds-write-via-apac-decoder
    label: >-
      VulnCheck Advisory: FFmpeg before 8.1.3 and 9.x before 9.0.2 Heap
      Out-of-Bounds Write via APAC Decoder
tags:
  - cve.org
ingestedAt: '2026-11-09T20:27:27.075Z'
---

## Overview

FFmpeg before 8.1.3 and 9.x before 9.0.2 contains a heap out-of-bounds write vulnerability in the APAC decoder in libavcodec/apac.c caused by an unreset bitstream index. Attackers can supply a crafted APAC file whose growing bitstream_index triggers an integer overflow, bypassing the reallocation check so memcpy() corrupts heap memory or crashes the application.

## Affected

- `FFmpeg < 8.1.3`
- `FFmpeg >= 9.0 < 9.0.2`

## Remediation

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