# CVE-2026-66036: FFmpeg heap out-of-bounds write in vf_hqdn3d filter

Source: https://junglewise.ai/threats/cve-2026-66036-ffmpeg-heap-out-of-bounds-write-in-vf-hqdn3d-filter  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-24. Updated: 2026-07-24  
License: CC BY 4.0 with a link back

CVE-2026-66036 · Severity: high · CVSS 8.8 · Published 2026-07-24

FFmpeg, a widely used multimedia framework for processing video and audio, contains a security flaw in its high-quality denoising filter (hqdn3d). An attacker can provide a specially crafted video file that, when processed with specific settings, causes the software to crash or potentially execute unauthorized code. This could lead to a total compromise of the system processing the video or the theft of sensitive data.

Technologies: [Ffmpeg](https://junglewise.ai/threats/technologies/ffmpeg). Vendors: [Ffmpeg](https://junglewise.ai/threats/vendors/ffmpeg).

## Quick answers

**Is CVE-2026-66036 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-66036 being exploited in the wild.

**How severe is CVE-2026-66036?** High severity, with a CVSS score of 8.8, published 24 July 2026.

**Which products and versions are affected?** Ffmpeg through 8.1.2.

**Is there a fix for CVE-2026-66036?** A patch was published on 2026-07-12: Fix committed to FFmpeg master branch Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-66036 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-66036?** Check whether you run Ffmpeg at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

A heap-based buffer overflow exists in FFmpeg's vf_hqdn3d filter due to improper handling of dynamic frame resolution changes. When filtergraph reinitialization is disabled (via -reinit_filter 0), the vf_hqdn3d.config_input() function may allocate line-history buffers based on an initial small frame size. If a subsequent frame in the same stream has a larger resolution, the denoise_spatial() function writes data into these undersized buffers, leading to an out-of-bounds write. This can result in heap memory corruption, application crashes, or arbitrary code execution. The vulnerability is fixed in commit 5d7112c.

## Affected products

- FFmpeg FFmpeg through 8.1.2

## Timeline

- 2026-07-12: patched: Fix committed to FFmpeg master branch
- 2026-07-24: disclosed: CVE-2026-66036 published

## References

- [https://code.ffmpeg.org/FFmpeg/FFmpeg/commit/5d7112c60e6f0f0742ce47d448e6da0718a70f4c](https://code.ffmpeg.org/FFmpeg/FFmpeg/commit/5d7112c60e6f0f0742ce47d448e6da0718a70f4c)
- [https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/23783](https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/23783)
- [https://www.vulncheck.com/advisories/ffmpeg-heap-out-of-bounds-write-in-vf-hqdn3d-filter](https://www.vulncheck.com/advisories/ffmpeg-heap-out-of-bounds-write-in-vf-hqdn3d-filter)

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