FFmpeg through 9.0.2 Uninitialized Stack Memory Disclosure via SANM Codec 23

Advisories

FFmpeg through 9.0.2 Uninitialized Stack Memory Disclosure via SANM Codec 23

Severity: medium
Date: 11/9/2026
Affecting: FFmpeg >= 8.0, <= 9.0.2
CVE: CVE-2026-125266
CWE: CWE-908 Use of Uninitialized Resource
CVSS: 4.8
CVSS V4 Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
References: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/25718
Patch Commit
https://github.com/FFmpeg/FFmpeg/blob/n9.0.2/libavcodec/sanm.c#L799
https://github.com/FFmpeg/FFmpeg
Credit: Joshua Rogers (AISLE Research), Michael Niedermayer
Description: FFmpeg through 9.0.2 contains an uninitialized stack memory disclosure vulnerability in old_codec23() of libavcodec/sanm.c that leaks stack bytes into decoded frames. Attackers can supply a crafted LucasArts SMUSH/SANM animation using codec 23 with an inline table to expose decoder process stack memory in output video.

Ready to get Started?

Explore VulnCheck, a next-generation Cyber Threat Intelligence platform, which provides exploit and vulnerability intelligence to help you prioritize and remediate vulnerabilities that matter.

Vulnerability Prioritization
Prioritize vulnerabilities that matter based on the threat landscape and defer vulnerabilities that don't.
Early Warning System
Real-time alerting of changes in the vulnerability landscape so that you can take action before the attacks start.

Schedule a Demo