---
id: "CVE-2026-125171"
page: "https://infrastack.ai/live/CVE-2026-125171"
kind: "vulnerability"
aliases: ["CVE-2026-125171"]
title: "FFmpeg: crafted Musepack SV7 file reads past audio buffer"
severity: "medium"
cvss: 6.9
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["ffmpeg", "media-processing", "package", "self-hosted"]
not_affected_if: ["no-musepack-input", "trusted-files-only"]
published_at: "2026-11-09T19:16:51+00:00"
first_seen_at: "2026-11-09T19:28:16+00:00"
updated_at: "2026-11-09T19:30:22+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-125171", "first_seen_at": "2026-11-09T19:28:16+00:00"}]
exploit_sources: []
---

# FFmpeg: crafted Musepack SV7 file reads past audio buffer

Link for people: https://infrastack.ai/live/CVE-2026-125171 (this .md is for agents)

FFmpeg's Musepack SV7 decoder does not check the declared size of the final frame, so a crafted file makes it read past the audio buffer. An attacker can crash a program that decodes the file or leak heap memory.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Run `ffmpeg -version` and compare against the fixed release named in the linked patch.
- Check whether your application decodes user-supplied Musepack (.mpc) files through FFmpeg.

## Timeline

- 2026-11-09T19:28:16+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-125171

## Documents

- [advisory] Third-party advisory: www.vulncheck.com https://www.vulncheck.com/advisories/ffmpeg-through-9.0.2-out-of-bounds-read-in-musepack-sv7-decoder-via-mpc7-c
- [fix] Patch: github.com https://github.com/FFmpeg/FFmpeg/commit/5d59b7c45d7142bddd13ddc8891e72c5c7dc991b

## From the sources

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.

---

_Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai_