CVE-2026-125246

MEDIUM 4.7

FFmpeg through 9.0.2 Assertion Failure DoS via cbs_jpeg_assemble_fragment

CVSS Score

4.7

EPSS Score

0.0%

EPSS Percentile

0th

FFmpeg through 9.0.2 contains a denial of service vulnerability in cbs_jpeg_assemble_fragment() that miscounts 0xff stuffing bytes in JPEG scan headers. Attackers can supply a crafted JPEG/MJPEG stream with 0xff in the scan header, triggering an av_assert0 abort when CBS-based bitstream filters process it.

CWE	CWE-617
Vendor	ffmpeg
Product	ffmpeg
Published	Nov 9, 2026

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CVSS v3 Breakdown

CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:H

Attack Vector

Local

Attack Complexity

High

Privileges Required

None

User Interaction

Required

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Affected Versions

FFmpeg / FFmpeg

0 ≤ 9.0.2

References

NVD ↗ CVE.org ↗ EPSS Data ↗

code.ffmpeg.org: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/25232 github.com: https://github.com/FFmpeg/FFmpeg/commit/ee457fdcdb3a069ef35910a2e1cacff10906b131 github.com: https://github.com/FFmpeg/FFmpeg/blob/n9.0.2/libavcodec/cbs_jpeg.c#L365 github.com: https://github.com/FFmpeg/FFmpeg vulncheck.com: https://www.vulncheck.com/advisories/ffmpeg-through-9.0.2-assertion-failure-dos-via-cbs-jpeg-assemble-fragment

Credits

Joshua Rogers (AISLE Research) Michael Niedermayer