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.

CVSS 4.0

8.7CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

CVSS 3.1

8.8CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

EPSS

0.6% chance of exploitation in the next 30 days; higher than 50% of CVEs (scores of 2026-10-25)

CWE

CWE-122

Published

2026-07-22

Modified

2026-10-24

Record from

the NVD, synced 2026-10-24

Affected

• ffmpeg:ffmpeg

References

• https://code.ffmpeg.org/FFmpeg/FFmpeg/commit/dbd495f066a85ba96b17433f4306582aa37c3951
• https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/23657
• https://www.vulncheck.com/advisories/ffmpeg-heap-buffer-overflow-via-vobsub-subtitle-demuxer

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