---
id: "CVE-2026-125223"
page: "https://infrastack.ai/live/CVE-2026-125223"
kind: "vulnerability"
aliases: ["CVE-2026-125223"]
title: "FFmpeg: VP9 decoder leaks memory on malformed streams, exhausting process memory"
severity: "medium"
cvss: 5.7
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["ffmpeg", "media-processing", "package", "self-hosted", "vp9"]
not_affected_if: ["no-vp9-decoding", "other-versions", "trusted-input-only"]
published_at: "2026-11-09T19:16:59+00:00"
first_seen_at: "2026-11-09T19:28:19+00:00"
updated_at: "2026-11-09T19:32:01+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-125223", "first_seen_at": "2026-11-09T19:28:19+00:00"}]
exploit_sources: []
---

# FFmpeg: VP9 decoder leaks memory on malformed streams, exhausting process memory

Link for people: https://infrastack.ai/live/CVE-2026-125223 (this .md is for agents)

FFmpeg versions 8.0 through 9.0.2 have a VP9 decoder bug where error paths skip resetting the CBS fragment, so packet buffers and units leak. A crafted VP9 stream with invalid tile sizes, decoded with slice threading, can exhaust memory in the decoding application.

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

## How to check

- Run `ffmpeg -version` and compare against the affected range `8.0` through `9.0.2`.
- Check whether VP9 decoding with slice threading is used on untrusted input.

## Fix

- Move to a version after `9.0.2` that includes the upstream patch; the exact fixed version is unknown from the sources.

## Timeline

- 2026-11-09T19:28:19+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-125223

## Documents

- [advisory] Third-party advisory: www.vulncheck.com https://www.vulncheck.com/advisories/ffmpeg-8.0-through-9.0.2-memory-leak-in-vp9-decoder-via-vp9-decode-frame
- [fix] Patch: github.com https://github.com/FFmpeg/FFmpeg/commit/bcce3232016695f5e482867519c45727a0a2a2c9

## From the sources

FFmpeg 8.0 through 9.0.2 contains a memory leak vulnerability in the VP9 decoder that allows attackers to exhaust memory because vp9_decode_frame() skips resetting the CBS fragment on error paths. Attackers can supply a crafted VP9 stream with invalid tile sizes decoded with slice threading to leak packet buffers and units, exhausting memory in the decoding application.

---

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