Buffer overflow in Ffmpeg
CVE-2026-125244
FFmpeg before 8.1.3 and 9.x before 9.0.2 contains an out-of-bounds write vulnerability in the VVC decoder's sh_entry_points() function in libavcodec/vvc/ps.c. Attackers can supply a crafted VVC (H.266) bitstream whose SPS/PPS tile and WPP layout produces excess entry points, overflowing entry_point_start_ctu and corrupting decoder memory.
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/24537 (issue-tracking)
- github.com/FFmpeg/FFmpeg (product)
- github.com/FFmpeg/FFmpeg/blob/n9.0.1/libavcodec/vvc/ps.c (technical-description)
- github.com/FFmpeg/FFmpeg/commit/a809a784ec9ff9910161c6c9554a041941d6ccce (patch)
- www.vulncheck.com/advisories/ffmpeg-before-8.1.3-and-9-x-before-9.0.2-vvc-decod… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-125244?
- CVE-2026-125244 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-2026-125244?
- High severity. CVSS v3 base score is 7.8 out of 10.