---
id: "CVE-2026-125205"
page: "https://infrastack.ai/live/CVE-2026-125205"
kind: "vulnerability"
aliases: ["CVE-2026-125205"]
title: "FFmpeg: crafted AV1 file exhausts memory and crashes media processing"
severity: "medium"
cvss: 6.8
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["av1", "ffmpeg", "media-processing", "package"]
not_affected_if: ["filter-unused", "trusted-input-only"]
published_at: "2026-11-09T19:16:57+00:00"
first_seen_at: "2026-11-09T19:28:18+00:00"
updated_at: "2026-11-09T19:31:30+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-125205", "first_seen_at": "2026-11-09T19:28:18+00:00"}]
exploit_sources: []
---

# FFmpeg: crafted AV1 file exhausts memory and crashes media processing

Link for people: https://infrastack.ai/live/CVE-2026-125205 (this .md is for agents)

FFmpeg's av1_frame_merge bitstream filter buffers AV1 data without limit when a temporal delimiter is never sent. A crafted .obu file opened by the AV1 OBU or Annex B demuxer can exhaust memory and cause a denial of service.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the FFmpeg version with `ffmpeg -version`; affected releases are listed as through `9.0.2`
- Check whether av1_frame_merge is used, for example in a pipeline that processes untrusted .obu or Annex B input

## Timeline

- 2026-11-09T19:28:18+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-125205

## Documents

- [advisory] Third-party advisory: www.vulncheck.com https://www.vulncheck.com/advisories/ffmpeg-through-9.0.2-memory-exhaustion-via-av1-frame-merge-bitstream-filter
- [fix] Patch: github.com https://github.com/FFmpeg/FFmpeg/commit/c90bbc2036bac67e95777638bdc86157a775858a

## From the sources

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.

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_Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai_