---
id: "CVE-2026-125239"
page: "https://infrastack.ai/live/CVE-2026-125239"
kind: "vulnerability"
aliases: ["CVE-2026-125239"]
title: "FFmpeg: crafted HEVC video lets attackers corrupt memory on Windows"
severity: "high"
cvss: 7.3
epss: null
exploited: false
status: "open"
category: "package"
products: [{"name": "ffmpeg", "fixed": [], "affected": "<= 9.0.2", "ecosystem": "vendor"}]
ecosystems: []
tags: ["ffmpeg", "hevc", "media-processing", "package", "windows"]
not_affected_if: ["no-hevc-decoding", "non-windows", "software-decoding-only"]
published_at: "2026-11-09T19:17:02+00:00"
first_seen_at: "2026-11-09T19:28:20+00:00"
updated_at: "2026-11-09T19:31:44+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-125239", "first_seen_at": "2026-11-09T19:28:20+00:00"}, {"source": "analyst", "url": "https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/25136", "first_seen_at": "2026-11-09T19:31:44+00:00", "cites": ["https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/25136"]}]
exploit_sources: []
---

# FFmpeg: crafted HEVC video lets attackers corrupt memory on Windows

Link for people: https://infrastack.ai/live/CVE-2026-125239 (this .md is for agents)

FFmpeg through 9.0.2 has a heap buffer overflow in its DXVA2, D3D11VA and D3D12VA HEVC decoding code on Windows. A crafted HEVC bitstream with many non-uniformly spaced tiles writes controlled 16-bit values past fixed-size arrays, corrupting memory.

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

## Affected

- vendor:ffmpeg affected <= 9.0.2 fixed no fixed version listed

## How to check

- Run `ffmpeg -version`; versions 9.0.2 and earlier are affected (no fixed release yet).
- Only Windows builds using DXVA2, D3D11VA or D3D12VA hardware HEVC decoding are affected (libavcodec/dxva2_hevc.c).
- Also check apps that embed FFmpeg/libavcodec on Windows and decode untrusted HEVC with hwaccel enabled.
- Workaround (not from the advisory, which lists none): force software HEVC decoding, e.g. don't pass -hwaccel dxva2/d3d11va/d3d12va.

## Fix

No released fix yet. Candidate fix is open FFmpeg PR 25136 (milestone 'FFmpeg 9.1 branching'), not merged as of 2026-11-09. Until then, build from master after it merges or disable DXVA2/D3D11VA/D3D12VA HEVC hwaccel.

## Timeline

- 2026-11-09T19:28:20+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-125239
- 2026-11-09T19:31:44+00:00 analyst https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/25136 — VulnCheck advisory read: affects <=9.0.2, credit J. Rogers/AISLE & M. Niedermayer, no fixed release named. Linked PR 25136 is open/unmerged, target milestone 9.1. NVD page unreadable via fetch. Search tools unavailable (web-cli missing), no discussion check. Nothing marked verified: no fix exists in a primary release.

## Documents

- [advisory] Third-party advisory: www.vulncheck.com https://www.vulncheck.com/advisories/ffmpeg-through-9.0.2-heap-buffer-overflow-via-hevc-dxva-tile-parameters
- [fix] FFmpeg PR 25136: libavcodec fixes (HEVC/AV1 hwaccel tile arrays, Vulkan) - open https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/25136

## From the sources

FFmpeg through 9.0.2 contains a heap buffer overflow vulnerability in ff_dxva2_hevc_fill_picture_parameters() that allows attackers to corrupt memory via unbounded non-uniform tile counts. Attackers can supply crafted HEVC bitstreams with many non-uniformly spaced tiles to write controlled 16-bit values past fixed-size DXVA arrays during DXVA2, D3D11VA, or D3D12VA decoding on Windows.

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