CVE-2026-125203
Published:November 09, 2026
Updated:November 10, 2026
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.
Affected Packages
ffmpeg (CONAN):
Affected version(s) >=7.0.1 <9.0.2 || >=4.2.1 <9.0.2 || >=5.0 <9.0.2 || =9.0.1 <9.0.2 || >=8.0 <9.0.2 || >=6.0 <9.0.2Fix Suggestion:
Update to version 9.0.2https://github.com/FFmpeg/FFmpeg.git (GITHUB):
Affected version(s) >=v0.6 <n8.1.3 || =ffmpeg-0.6.3 <n8.1.3 || >=n0.6.4 <n8.1.3 || >=n1.0 <n8.1.3 || >=n2.0 <n8.1.3 || >=n3.0 <n8.1.3 || >=n4.0 <n8.1.3 || >=n5.0 <n8.1.3 || >=n6.0 <n8.1.3 || >=n7.0 <n8.1.3 || >=n8.0 <n8.1.3Fix Suggestion:
Update to version n8.1.3https://github.com/FFmpeg/FFmpeg.git (GITHUB):
Affected version(s) =n8.2-dev <n9.0.2 || >=n9.0 <n9.0.2Fix Suggestion:
Update to version n9.0.2Related Resources (8)
Do you need more information?
Contact UsCVSS v4
Base Score:
8.5
Attack Vector
LOCAL
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
PASSIVE
Vulnerable System Confidentiality
HIGH
Vulnerable System Integrity
HIGH
Vulnerable System Availability
HIGH
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
7.8
Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Weakness Type (CWE)
Out-of-bounds Write