---
id: CVE-2026-125191
title: FFmpeg through 9.0.2 V4L2 M2M Decoder Deadlock via Reference Count Leak
summary: >-
  FFmpeg through 9.0.2 contains a reference count leak in
  libavcodec/v4l2_buffers.c that allows attackers to deadlock the V4L2 mem2mem
  decoder on multi-plane capture formats. Attackers can supply crafted H.264,
  HEVC, or VP9 streams with re…
severity: medium
cvss: 4.7
cvssVector: 'CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:H'
cvssSource: cna
cwe:
  - CWE-911
vendor: FFmpeg
product: FFmpeg
affected:
  - FFmpeg <= 9.0.2
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-11-09T21:01:56.596542Z'
published: '2026-11-09'
updated: '2026-11-09'
sourceUpdated: '2026-11-09T21:06:57.097Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-125191'
references:
  - url: 'https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/25682'
  - url: >-
      https://github.com/FFmpeg/FFmpeg/commit/4d2d58efa9b9f3802893b1db0ea1edfbe1cc66ef
    label: Patch Commit
  - url: >-
      https://github.com/FFmpeg/FFmpeg/blob/n9.0.2/libavcodec/v4l2_buffers.c#L274
  - url: 'https://github.com/FFmpeg/FFmpeg'
  - url: >-
      https://www.vulncheck.com/advisories/ffmpeg-through-9.0.2-v4l2-m2m-decoder-deadlock-via-reference-count-leak
    label: >-
      VulnCheck Advisory: FFmpeg through 9.0.2 V4L2 M2M Decoder Deadlock via
      Reference Count Leak
tags:
  - cve.org
ingestedAt: '2026-11-09T19:18:02.606Z'
---

## Overview

FFmpeg through 9.0.2 contains a reference count leak in libavcodec/v4l2_buffers.c that allows attackers to deadlock the V4L2 mem2mem decoder on multi-plane capture formats. Attackers can supply crafted H.264, HEVC, or VP9 streams with resolution changes, making ff_v4l2_m2m_codec_reinit() wait forever and hang the decoding application.

## Affected

- `FFmpeg <= 9.0.2`

## Remediation

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