Bug 2570723 (CVE-2026-125257)

Summary: CVE-2026-125257 ffmpeg: ffmpeg: Arbitrary code execution via crafted Nellymoser audio encoding
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
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Hardware: All   
OS: Linux   
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A flaw was found in FFmpeg. An off-by-one heap-based buffer overflow exists in the Nellymoser audio encoder during dynamic exponent calculations. By supplying specially crafted audio data to an application encoding Nellymoser audio with trellis optimization enabled, an attacker can overwrite adjacent heap memory. This vulnerability can lead to arbitrary code execution or cause an application crash, 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 20:17:52 UTC
FFmpeg through 9.0.2 contains an off-by-one heap overflow vulnerability in get_exponent_dynamic() in libavcodec/nellymoserenc.c that allows writing one element past the opt and path allocations. Attackers can supply crafted audio to applications encoding Nellymoser with trellis enabled, causing idx to equal OPT_SIZE and overwrite adjacent heap memory.