Integer overflow in Ffmpeg
CVE-2026-125251
FFmpeg through 9.0.2 contains an integer overflow vulnerability in the VVC decoder alloc_frame() function in libavcodec/vvc/refs.c that undersizes the reference picture list allocation on 32-bit builds. Attackers can supply a crafted VVC (H.266) file with a very large number of NAL units per access unit to trigger heap out-of-bounds writes and corrupt memory.
Vulnerability class: Integer Overflow
Published .
CVSS v3 metric
CVSS v3 base score 7.0 (High). Vector: CVSS:3.1/AV:L/AC:H/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/25572 (issue-tracking)
- github.com/FFmpeg/FFmpeg (product)
- github.com/FFmpeg/FFmpeg/blob/n9.0.2/libavcodec/vvc/refs.c (technical-description)
- github.com/FFmpeg/FFmpeg/commit/053660fdb0d2403b838690689c47ad7685c3b10b (patch)
- www.vulncheck.com/advisories/ffmpeg-through-9.0.2-vvc-decoder-heap-out-of-bound… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-125251?
- CVE-2026-125251 is a high-severity vulnerability in Ffmpeg, classified under Integer Overflow or Wraparound. CVSS score: 7.0/10. Published 2026-11-09.
- How severe is CVE-2026-125251?
- High severity. CVSS v3 base score is 7.0 out of 10.