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.
History

Mon, 09 Nov 2026 19:30:00 +0000

Type Values Removed Values Added
Description 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.
Title FFmpeg through 9.0.2 Heap Overflow via Nellymoser Encoder Trellis Search
First Time appeared Ffmpeg
Ffmpeg ffmpeg
Weaknesses CWE-193
CPEs cpe:2.3:a:ffmpeg:ffmpeg:*:*:*:*:*:*:*:*
Vendors & Products Ffmpeg
Ffmpeg ffmpeg
References
Metrics cvssV3_1

{'score': 7, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H'}

cvssV4_0

{'score': 7.3, 'vector': 'CVSS:4.0/AV:L/AC:H/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published: 2026-11-09T19:12:01.153Z

Updated: 2026-11-09T19:12:01.153Z

Reserved: 2026-11-09T18:15:32.455Z

Link: CVE-2026-125257

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-11-09T20:18:11.930

Modified: 2026-11-10T21:46:33.920

Link: CVE-2026-125257

cve-icon Redhat

No data.