{"id":"CVE-2026-125203","state":"PUBLISHED","title":"FFmpeg before 8.1.3 and 9.x before 9.0.2 Heap Buffer Overflow in Cook Multichannel Decoder","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.","publishedAt":"2026-11-09T19:11:22.136Z","updatedAt":"2026-11-09T19:11:22.136Z","severity":{"score":8.5,"label":"High","version":"4.0","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","source":"VulnCheck"},"assigner":"VulnCheck","products":["FFmpeg FFmpeg"],"affected":[{"vendor":"FFmpeg","product":"FFmpeg","packageURL":"pkg:github/ffmpeg/ffmpeg","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThan":"8.1.3","versionType":"custom"},{"version":"9.0","status":"affected","lessThan":"9.0.2","versionType":"custom"}],"repo":"https://code.ffmpeg.org/FFmpeg/FFmpeg"}],"references":["https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/24485","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://www.vulncheck.com/advisories/ffmpeg-before-8.1.3-and-9-x-before-9.0.2-heap-buffer-overflow-in-cook-multichannel-decoder"],"weaknesses":["CWE-787"],"ingestedAt":"2026-11-09T19:14:06.399Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/125xxx/CVE-2026-125203.json","commit":"61d6df80db1b12b1399aa01bc455626e606d2471","baselineCommit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-125203","state":"PUBLISHED","datePublished":"2026-11-09T19:11:22.136Z","dateUpdated":"2026-11-09T19:11:22.136Z","assignerShortName":"VulnCheck","assignerOrgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","dateReserved":"2026-11-09T18:15:12.867Z"},"containers":{"cna":{"title":"FFmpeg before 8.1.3 and 9.x before 9.0.2 Heap Buffer Overflow in Cook Multichannel Decoder","descriptions":[{"lang":"en","value":"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. 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