Integer overflow in Ffmpeg
CVE-2026-125253
FFmpeg through 9.0.2 contains an integer overflow in cbs_vp9_split_fragment() in libavcodec/cbs_vp9.c that wraps the superframe size check on 32-bit builds. Attackers can supply a crafted VP9 packet with a forged superframe index containing near-2^32 frame sizes, causing out-of-bounds reads that crash 32-bit applications.
Vulnerability class: Integer 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/25232 (issue-tracking)
- github.com/FFmpeg/FFmpeg/commit/6280907da48c4dd78f95ef5c713a29c7702153a3 (patch)
- github.com/FFmpeg/FFmpeg/blob/n9.0.2/libavcodec/cbs_vp9.c (technical-description)
- github.com/FFmpeg/FFmpeg (product)
- www.vulncheck.com/advisories/ffmpeg-through-9.0.2-vp9-cbs-superframe-integer-ov… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-125253?
- CVE-2026-125253 is a medium-severity vulnerability in Ffmpeg, classified under Integer Overflow or Wraparound. CVSS score: 5.3/10. Published 2026-11-09.
- How severe is CVE-2026-125253?
- Medium severity. CVSS v3 base score is 5.3 out of 10.