---
id: "CVE-2026-125264"
page: "https://infrastack.ai/live/CVE-2026-125264"
kind: "vulnerability"
aliases: ["CVE-2026-125264"]
title: "FFmpeg: crafted JPEG XL header can exhaust CPU during parsing"
severity: "medium"
cvss: 6.8
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["ffmpeg", "jpeg-xl", "libavcodec", "media-processing", "package"]
not_affected_if: ["no-untrusted-jpeg-xl-input"]
published_at: "2026-11-09T20:18:12+00:00"
first_seen_at: "2026-11-09T20:48:14+00:00"
updated_at: "2026-11-09T20:49:47+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-125264", "first_seen_at": "2026-11-09T20:48:14+00:00"}]
exploit_sources: []
---

# FFmpeg: crafted JPEG XL header can exhaust CPU during parsing

Link for people: https://infrastack.ai/live/CVE-2026-125264 (this .md is for agents)

FFmpeg's JPEG XL frame header parser does not check table-of-contents entry counts against the remaining input. A crafted JPEG XL file with a huge TOC count makes the parser loop excessively and exhaust CPU, causing 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`; versions through `9.0.2` are listed as affected.
- Look for FFmpeg use that decodes or probes untrusted JPEG XL images, such as upload or thumbnail pipelines.

## Timeline

- 2026-11-09T20:48:14+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-125264

## Documents

- [advisory] Third-party advisory: www.vulncheck.com https://www.vulncheck.com/advisories/ffmpeg-through-9.0.2-cpu-exhaustion-via-jpeg-xl-parser-toc-count
- [fix] Patch: github.com https://github.com/FFmpeg/FFmpeg/commit/bc896c613ec0d4ad0108d62fbdda0196f69e7121

## From the sources

FFmpeg through 9.0.2 contains an uncontrolled resource consumption vulnerability in parse_frame_header() in libavcodec/jpegxl_parser.c that fails to validate TOC entry counts against remaining input. Attackers can supply a crafted JPEG XL frame header with a permuted TOC and huge toc_count, making the parser loop excessively and exhaust CPU.

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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_