Bug 2493952 (CVE-2026-58049)

Summary: CVE-2026-58049 FFmpeg: FFmpeg: Memory corruption via crafted RASC video stream
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: alinfoot, bbrownin, dtrifiro, gtanzill, jbuscemi, jkoehler, lphiri, rbryant, weaton
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: ---
Doc Text:
A flaw was found in FFmpeg's RASC video decoder. A remote attacker could exploit this by providing a crafted media stream using the RASC FourCC (Four Character Code), which is then decoded by libavcodec. This vulnerability triggers a bitstream-controlled out-of-bounds heap write and an adjacent out-of-bounds read, leading to memory corruption. This can result in a denial of service or potentially arbitrary code execution.
 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: 2494551, 2494552, 2494553, 2494554, 2494555    
Bug Blocks:    

Description OSIDB Bzimport 2026-06-28 03:01:39 UTC 
FFmpeg's RASC video decoder (decode_dlta in libavcodec/rasc.c) performs 32-bit reads and writes at the row cursor before the NEXT_LINE row-boundary check and validates the DLTA region in pixel rather than byte units, so a DLTA run on a PAL8 frame can access several bytes past the row allocation. A crafted media stream using the RASC FourCC, decoded by libavcodec, triggers a bitstream-controlled out-of-bounds heap write and adjacent out-of-bounds read, leading to memory corruption.