CVE-2026-125203

high

Description

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.

References

https://www.vulncheck.com/advisories/ffmpeg-before-8.1.3-and-9-x-before-9.0.2-heap-buffer-overflow-in-cook-multichannel-decoder

https://github.com/FFmpeg/FFmpeg/commit/3e09f5e24eb277a6d011745ff03e602f61c5c171

https://github.com/FFmpeg/FFmpeg/blob/n9.0.1/libavcodec/cook.c#L1294

https://github.com/FFmpeg/FFmpeg

https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-120292

https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/24485

Details

Source: Mitre, NVD

Published: 2026-11-09

Updated: 2026-11-10

Risk Information

CVSS v2

Base Score: 7.2

Vector: CVSS2#AV:L/AC:L/Au:N/C:C/I:C/A:C

Severity: High

CVSS v3

Base Score: 7.8

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

Severity: High

CVSS v4

Base Score: 8.5

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

Severity: High

EPSS

EPSS: 0.00141