Bug 2571034 (CVE-2026-125203)

Summary: CVE-2026-125203 ffmpeg: ffmpeg: Arbitrary code execution via heap buffer overflow in Cook multichannel decoder
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: unspecifiedCC: bbrownin
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in FFmpeg. An attacker could exploit this vulnerability by enticing an application using FFmpeg to process a specially crafted RealMedia Cook audio stream containing overlapping subpacket channel masks. This issue triggers a heap-based buffer overflow during decoding, which may allow arbitrary code execution or crash the application, resulting in a denial of service (DoS).
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2026-11-10 20:37:29 UTC 
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.