Bug 2564498 (CVE-2026-120246)

Summary: CVE-2026-120246 ffmpeg: ffmpeg: Information disclosure via uninitialized palette entries in CDXL decoder
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: bbrownin
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: ---
Doc Text:
A flaw was found in FFmpeg. This vulnerability leads to information disclosure when processing a specially crafted CDXL media file. By tricking a user or automated service into decoding a file that references uninitialized color palette entries, an attacker can cause sensitive internal stack memory to leak into the decoded output frames.
 Story Points: ---
Clone Of: Environment:
Last Closed: Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On: 2565015, 2565018, 2565022, 2565028, 2565031, 2565035, 2565038, 2565041, 2565045, 2565047, 2565050, 2565054    
Bug Blocks:    

Description OSIDB Bzimport 2026-11-01 01:02:13 UTC 
FFmpeg 4.4 through 9.0.2 contains a use of uninitialized variable vulnerability in the CDXL decoder that leaks stack memory into decoded pixels via unfilled HAM palette entries. Attackers can craft a type-0 CDXL file whose HAM pixels select unfilled new_palette entries in cdxl_decode_ham8() or cdxl_decode_ham6(), exposing stack bytes and pointer fragments in the BGR24 output.