# CVE-2026-125264: FFmpeg JPEG XL parser uncontrolled resource consumption

Source: https://junglewise.ai/threats/cve-2026-125264-ffmpeg-through-9-0-2-contains-an-uncontrolled-resource  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-11-09. Updated: 2026-11-09  
License: CC BY 4.0 with a link back

CVE-2026-125264 · Severity: medium · CVSS 5.5 · Published 2026-11-09

FFmpeg is a multimedia processing library used to encode and decode video, audio, and image formats. A flaw in the JPEG XL parser allows attackers to supply crafted files that cause excessive CPU consumption, potentially causing application hangs or denial of service. This affects any application using FFmpeg to process untrusted image files.

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

## Quick answers

**Is CVE-2026-125264 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-125264 being exploited in the wild.

**How severe is CVE-2026-125264?** Medium severity, with a CVSS score of 5.5, published 9 November 2026.

**Which products and versions are affected?** Ffmpeg through 9.0.2.

**Is there a fix for CVE-2026-125264?** Yes: fixed in FFmpeg 9.1. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-125264 attacked?** It is attacked with local access, in a software library.

**Am I affected by CVE-2026-125264?** 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.

## How to fix

- Fixed in FFmpeg 9.1

## Technical details

An uncontrolled resource consumption vulnerability exists in parse_frame_header() in libavcodec/jpegxl_parser.c, where the parser fails to validate TOC (table of contents) entry counts against the amount of remaining input data. An attacker can craft a JPEG XL frame header with a permuted TOC and oversized toc_count value, causing the parser to loop excessively and exhaust CPU. The vulnerability is triggered by processing malformed JPEG XL image files and requires no authentication or user interaction beyond opening the file.

## Affected products

- FFmpeg FFmpeg through 9.0.2

## Timeline

- 2026-11-09: disclosed
- 2026-11-03: patched: Merged in PR #25569

## References

- [https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/25569](https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/25569)
- [https://github.com/FFmpeg/FFmpeg](https://github.com/FFmpeg/FFmpeg)

## Related threats

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- [FFmpeg double free in H.264 SEI message handling](https://junglewise.ai/threats/cve-2026-125269-ffmpeg-through-9-0-2-contains-a-double-free-vulnerability-in)
- [FFmpeg heap out-of-bounds write in APAC decoder](https://junglewise.ai/threats/cve-2026-125267-ffmpeg-before-8-1-3-and-9-x-before-9-0-2-contains-a-heap-out-of)
- [FFmpeg use-after-free in NVIDIA codec decoding](https://junglewise.ai/threats/cve-2026-125265-ffmpeg-through-9-0-2-contains-a-use-after-free-vulnerability-in)
- [FFmpeg LCEVC dimension validation bypass memory exhaustion](https://junglewise.ai/threats/cve-2026-125263-ffmpeg-9-0-through-9-0-2-built-with-liblcevc-dec-fails-to)