Out-of-bounds Read in Ffmpeg
CVE-2026-125270
FFmpeg through 9.0.2 contains a heap out-of-bounds read vulnerability in v4l2_buffer_swframe_to_buf() in libavcodec/v4l2_buffers.c that mishandles frames with negative linesize. Attackers can supply bottom-up AVI or PNM/PFM files that are transcoded to a V4L2 M2M encoder, crashing the application or leaking heap memory into encoded output.
Vulnerability class: Buffer Overflow
Published .
CVSS v3 metric
CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:L/I:N/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/24328 (issue-tracking)
- github.com/FFmpeg/FFmpeg/commit/b8f159858e2fd29dae4fa34d9e713bbf9bbf190e (patch)
- github.com/FFmpeg/FFmpeg/blob/n9.0.2/libavcodec/v4l2_buffers.c (technical-description)
- github.com/FFmpeg/FFmpeg (product)
- www.vulncheck.com/advisories/ffmpeg-through-9.0.2-heap-out-of-bounds-read-in-v4… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-125270?
- CVE-2026-125270 is a medium-severity vulnerability in Ffmpeg, classified under Out-of-bounds Read. CVSS score: 5.3/10. Published 2026-11-09.
- How severe is CVE-2026-125270?
- Medium severity. CVSS v3 base score is 5.3 out of 10.