Buffer overflow in Ffmpeg
CVE-2026-64830
FFmpeg versions 2.1 through 8.1.2 contains a heap buffer overflow vulnerability in the VobSub subtitle demuxer that allows attackers to corrupt adjacent heap memory by supplying a malicious .sub/.idx subtitle file declaring more distinct stream IDs than the fixed-size array bounds in libavformat/mpeg.c. Attackers can craft a subtitle file with excessive distinct stream IDs to trigger unbounded writes beyond the vobsub->q[] array boundary via ff_subtitles_queue_insert(), potentially achieving arbitrary code execution in any application using FFmpeg's VobSub demuxer.
Vulnerability class: Buffer Overflow
EPSS: 0.003 (27.1th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.
Affected products
- Ffmpeg — versions 2.1, dbd495f066a85ba96b17433f4306582aa37c3951
Weakness classification (CWE)
References
- disclosure@vulncheck.com (issue-tracking, Patch, Issue Tracking)
- disclosure@vulncheck.com (Patch, patch)
- disclosure@vulncheck.com (Third Party Advisory, third-party-advisory)
Frequently asked questions
- What is CVE-2026-64830?
- CVE-2026-64830 is a high-severity vulnerability in Ffmpeg, classified under Heap-based Buffer Overflow. CVSS score: 8.8/10. Published 2026-07-22.
- How severe is CVE-2026-64830?
- High severity. CVSS v3 base score is 8.8 out of 10.