Bug 2570381 (CVE-2026-125233)

Summary: CVE-2026-125233 ffmpeg: ffmpeg: Arbitrary code execution via heap buffer overflow in DVB subtitle encoder
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 can supply a specially crafted media file with multiple bitmap subtitle segments to trigger a heap-based buffer overflow during transcoding with the DVB (Digital Video Broadcasting) subtitle encoder. This issue stems from an incorrect buffer size calculation, causing the application to write beyond the allocated memory boundaries, which may lead to arbitrary code execution or 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 19:54:45 UTC
FFmpeg through 9.0.2 contains a heap buffer overflow vulnerability in dvbsub_encode() in libavcodec/dvbsubenc.c that undercounts each CLUT segment header by two bytes. Attackers can supply a file with many bitmap subtitle rectangles that, when transcoded to the dvbsub encoder, writes past the output buffer and corrupts heap memory.