CVE-2026-66041

FFmpeg 7.0 through 8.1.2, fixed in commit 4da9812, contains a heap out-of-bounds write vulnerability in the vf_quirc filter that allows an attacker to corrupt heap memory by supplying a crafted PGS/SUP subtitle file with mismatched frame dimensions. Attackers can provide a subtitle file whose second presentation has larger dimensions than its first, causing av_image_copy_plane() to copy data exceeding the initial allocation size into the undersized libquirc grayscale image buffer, resulting in heap corruption and process crash with potential for code execution.

CVSS 4.0

7.7CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

CVSS 3.1

7.8CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

EPSS

0.5% chance of exploitation in the next 30 days; higher than 41% of CVEs (scores of 2026-10-25)

CWE

CWE-787

Published

2026-07-24

Modified

2026-10-24

Record from

the NVD, synced 2026-10-24

Affected

• ffmpeg:ffmpeg

References

• https://code.ffmpeg.org/FFmpeg/FFmpeg/commit/4da9812e25894fb51d62a8875cfa8eb39b5e20f5
• https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/23625
• https://www.vulncheck.com/advisories/ffmpeg-heap-out-of-bounds-write-via-vf-quirc-filter

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