---
id: CVE-2026-125199
title: FFmpeg through 9.0.2 Memory Leak in VC-1 Decoder via vc1_decode_frame()
summary: >-
  FFmpeg through 9.0.2 contains a memory leak vulnerability in
  vc1_decode_frame() in libavcodec/vc1dec.c that leaks slice buffers when
  init_get_bits8() fails. Attackers can supply crafted files with repeated
  oversized VC-1 slices exceeding…
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-401
vendor: FFmpeg
product: FFmpeg
affected:
  - FFmpeg >= 8.1 <= 9.0.2
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-11-09T21:01:24.435593Z'
published: '2026-11-09'
updated: '2026-11-09'
sourceUpdated: '2026-11-09T21:06:56.735Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-125199'
references:
  - url: 'https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/25718'
  - url: >-
      https://github.com/FFmpeg/FFmpeg/commit/afdc555aace698b88c86d3f33a7773a6c8ba2897
    label: Patch Commit
  - url: 'https://github.com/FFmpeg/FFmpeg/blob/n9.0.2/libavcodec/vc1dec.c#L896'
  - url: 'https://github.com/FFmpeg/FFmpeg'
  - url: >-
      https://www.vulncheck.com/advisories/ffmpeg-through-9.0.2-memory-leak-in-vc-1-decoder-via-vc1-decode-frame
    label: >-
      VulnCheck Advisory: FFmpeg through 9.0.2 Memory Leak in VC-1 Decoder via
      vc1_decode_frame()
tags:
  - cve.org
ingestedAt: '2026-11-09T19:18:02.601Z'
---

## Overview

FFmpeg through 9.0.2 contains a memory leak vulnerability in vc1_decode_frame() in libavcodec/vc1dec.c that leaks slice buffers when init_get_bits8() fails. Attackers can supply crafted files with repeated oversized VC-1 slices exceeding the bit reader limit to exhaust memory of decoding applications.

## Affected

- `FFmpeg >= 8.1 <= 9.0.2`

## Remediation

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