Out-of-bounds Read in Ffmpeg
CVE-2026-125211
FFmpeg through 9.0.2 contains an out-of-bounds read and invalid free vulnerability in aribcaption_trans_ass_subtitle() in libavcodec/libaribcaption.c that frees subtitle rectangles using region_count instead of num_rects. Attackers can supply crafted ARIB captions whose later region exceeds the 8 KiB AVBPrint limit, triggering cleanup that frees out-of-bounds pointers and corrupts the heap.
Vulnerability class: Buffer 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/24992 (issue-tracking)
- github.com/FFmpeg/FFmpeg (product)
- github.com/FFmpeg/FFmpeg/blob/n9.0.2/libavcodec/libaribcaption.c (technical-description)
- github.com/FFmpeg/FFmpeg/commit/4ec127c82678b06658e963291f272881dc878735 (patch)
- www.vulncheck.com/advisories/ffmpeg-through-9.0.2-heap-corruption-via-libaribca… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-125211?
- CVE-2026-125211 is a high-severity vulnerability in Ffmpeg, classified under Out-of-bounds Read. CVSS score: 7.0/10. Published 2026-11-09.
- How severe is CVE-2026-125211?
- High severity. CVSS v3 base score is 7.0 out of 10.