---
id: CVE-2026-125205
title: FFmpeg through 9.0.2 Memory Exhaustion via av1_frame_merge Bitstream Filter
summary: >-
  FFmpeg through 9.0.2 contains an unbounded memory allocation vulnerability in
  the av1_frame_merge bitstream filter that allows attackers to exhaust memory
  by never sending a temporal delimiter OBU. Attackers can supply a crafted .obu
  fil…
severity: medium
cvss: 5.5
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H'
cvssSource: cna
cwe:
  - CWE-770
vendor: FFmpeg
product: FFmpeg
affected:
  - FFmpeg <= 9.0.2
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-11-09T21:00:52.340829Z'
published: '2026-11-09'
updated: '2026-11-09'
sourceUpdated: '2026-11-09T21:06:56.405Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-125205'
references:
  - url: 'https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/25569'
  - url: >-
      https://github.com/FFmpeg/FFmpeg/commit/c90bbc2036bac67e95777638bdc86157a775858a
    label: Patch Commit
  - url: >-
      https://github.com/FFmpeg/FFmpeg/blob/n9.0.2/libavcodec/bsf/av1_frame_merge.c#L97
  - url: 'https://github.com/FFmpeg/FFmpeg'
  - url: >-
      https://www.vulncheck.com/advisories/ffmpeg-through-9.0.2-memory-exhaustion-via-av1-frame-merge-bitstream-filter
    label: >-
      VulnCheck Advisory: FFmpeg through 9.0.2 Memory Exhaustion via
      av1_frame_merge Bitstream Filter
tags:
  - cve.org
ingestedAt: '2026-11-09T19:18:02.598Z'
---

## Overview

FFmpeg through 9.0.2 contains an unbounded memory allocation vulnerability in the av1_frame_merge bitstream filter that allows attackers to exhaust memory by never sending a temporal delimiter OBU. Attackers can supply a crafted .obu file opened by the AV1 OBU or Annex B demuxers, forcing unlimited OBU buffering per temporal unit and causing denial of service.

## Affected

- `FFmpeg <= 9.0.2`

## Remediation

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