Is CVE-2026-125246 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-125246 being exploited in the wild.

How severe is CVE-2026-125246?

Medium severity, with a CVSS score of 4.7, published 9 November 2026.

Is there a fix for CVE-2026-125246?

Yes: fixed in FFmpeg 9.1 and later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-125246 attacked?

It is attacked over the network, in a software library.

Am I affected by CVE-2026-125246?

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.

CVE-2026-125246: FFmpeg denial of service in JPEG bitstream parsing

CVE-2026-125246 · Severity: medium · CVSS 4.7 · Published 2026-11-09

FFmpeg is a widely-used multimedia processing library that decodes and processes audio and video files. A malicious JPEG or MJPEG stream can cause FFmpeg to crash due to incorrect handling of byte-stuffing markers in scan headers, disrupting video playback and processing services that rely on FFmpeg.

Technologies: Ffmpeg. Vendors: Ffmpeg.

Quick answers

Is CVE-2026-125246 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-125246 being exploited in the wild.
How severe is CVE-2026-125246?: Medium severity, with a CVSS score of 4.7, published 9 November 2026.
Which products and versions are affected?: Ffmpeg through 9.0.2.
Is there a fix for CVE-2026-125246?: Yes: fixed in FFmpeg 9.1 and later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-125246 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2026-125246?: 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 and later

Technical details

The cbs_jpeg_assemble_fragment() function miscounts 0xff stuffing bytes in JPEG scan headers, causing CBS-based bitstream filters to miscalculate buffer sizes. Attackers supply a crafted JPEG/MJPEG stream with 0xff bytes in the scan header, triggering an av_assert0 abort when the bitstream is parsed. The fix counts byte-stuffing only in the entropy-coded portion of the scan data, not the header itself.

Affected products

FFmpeg FFmpeg through 9.0.2

Timeline

2026-11-09: disclosed
2026-10-25: patched

References

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