Buffer overflow in Ffmpeg
CVE-2026-125229
FFmpeg through 9.0.2 contains an out-of-bounds memory access vulnerability in the encode_frame() function of libavcodec/huffyuvenc.c, because encode_init() never validates minimum frame dimensions for the median predictor. Attackers can supply a tiny video, such as a 2-pixel-wide or 1-2-pixel-tall frame, that causes negative sub_median_pred lengths and out-of-bounds reads and writes when transcoded to huffyuv or ffvhuff, crashing the encoder.
Vulnerability class: Buffer Overflow
Published .
CVSS v3 metric
CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
Weakness classification (CWE)
References
- code.ffmpeg.org/FFmpeg/FFmpeg/pulls/25573 (issue-tracking)
- github.com/FFmpeg/FFmpeg (product)
- github.com/FFmpeg/FFmpeg/blob/n9.0.2/libavcodec/huffyuvenc.c (technical-description)
- github.com/FFmpeg/FFmpeg/commit/45f98d0819efe2b7ce93e9034b7e6a4ed6700621 (patch)
- www.vulncheck.com/advisories/ffmpeg-through-9.0.2-out-of-bounds-memory-access-i… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-125229?
- CVE-2026-125229 is a high-severity vulnerability in Ffmpeg, classified under Out-of-bounds Write. CVSS score: 7.8/10. Published 2026-11-09.
- How severe is CVE-2026-125229?
- High severity. CVSS v3 base score is 7.8 out of 10.