CVE-2026-125203

EUVD-2026-120292
FFmpeg before 8.1.3 and 9.x before 9.0.2 contains a heap buffer overflow vulnerability in the Cook multichannel decoder in libavcodec/cook.c that fails to verify subpacket channel masks are disjoint. Attackers can supply a crafted RealMedia Cook stream with overlapping subpacket masks, causing cook_decode_frame() to write decoded samples beyond allocated output planes in any application decoding the file.
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
VulnCheckCNA
7.8 HIGH
LOCAL
LOW
NONE
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Base Score
CVSS 3.x
EPSS Score
Percentile: Unknown
Early Detection
Affected products identified ahead of NVD analysis through intelligence sources (CNA/ADP records, vendor advisories, Enginsight analysis).
VendorProductVersionSource
ffmpegffmpeg
𝑥
< 8.1.3
CNA
ffmpegffmpeg
9.0 ≤
𝑥
< 9.0.2
CNA
Common Weakness Enumeration
References
https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/24485
https://github.com/FFmpeg/FFmpeg
https://github.com/FFmpeg/FFmpeg/blob/n9.0.1/libavcodec/cook.c#L1294
https://github.com/FFmpeg/FFmpeg/commit/3e09f5e24eb277a6d011745ff03e602f61c5c171
https://www.vulncheck.com/advisories/ffmpeg-before-8.1.3-and-9-x-before-9.0.2-heap-buffer-overflow-in-cook-multichannel-decoder