Out-of-bounds Read in Ffmpeg
CVE-2026-125171
FFmpeg through 9.0.2 contains an out-of-bounds read vulnerability in the Musepack SV7 decoder because mpc7_decode_init() does not validate lastframelen against MPC_FRAME_SIZE. Attackers can supply a crafted Musepack SV7 file declaring an oversized final frame, causing consumers of decoded frames to read past the audio buffer, leading to crashes or heap memory disclosure.
Vulnerability class: Buffer Overflow
Published .
CVSS v3 metric
CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
Weakness classification (CWE)
References
- code.ffmpeg.org/FFmpeg/FFmpeg/pulls/25074 (issue-tracking)
- github.com/FFmpeg/FFmpeg (product)
- github.com/FFmpeg/FFmpeg/blob/n9.0.2/libavcodec/mpc7.c (technical-description)
- github.com/FFmpeg/FFmpeg/commit/5d59b7c45d7142bddd13ddc8891e72c5c7dc991b (patch)
- www.vulncheck.com/advisories/ffmpeg-through-9.0.2-out-of-bounds-read-in-musepac… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-125171?
- CVE-2026-125171 is a medium-severity vulnerability in Ffmpeg, classified under Out-of-bounds Read. CVSS score: 6.1/10. Published 2026-11-09.
- How severe is CVE-2026-125171?
- Medium severity. CVSS v3 base score is 6.1 out of 10.