---
id: "CVE-2026-125267"
page: "https://infrastack.ai/live/CVE-2026-125267"
kind: "vulnerability"
aliases: ["CVE-2026-125267"]
title: "FFmpeg: crafted APAC audio file corrupts heap memory and crashes"
severity: "high"
cvss: 8.5
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["ffmpeg", "libavcodec", "media-processing", "package"]
not_affected_if: ["apac-decoder-not-used", "no-untrusted-input"]
published_at: "2026-11-09T20:18:13+00:00"
first_seen_at: "2026-11-09T20:48:14+00:00"
updated_at: "2026-11-09T20:49:39+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-125267", "first_seen_at": "2026-11-09T20:48:14+00:00"}]
exploit_sources: []
---

# FFmpeg: crafted APAC audio file corrupts heap memory and crashes

Link for people: https://infrastack.ai/live/CVE-2026-125267 (this .md is for agents)

FFmpeg's APAC audio decoder fails to reset a bitstream index, so a crafted APAC file can overflow an integer and write past a heap buffer. An attacker who gets a victim to open such a file can corrupt memory or crash the application.

_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 versions below.
- Check whether your build includes the APAC decoder (`ffmpeg -decoders | grep apac`).

## Fix

- FFmpeg `8.1.3` or later on the 8.x line.
- FFmpeg `9.0.2` or later on the 9.x line.

## Timeline

- 2026-11-09T20:48:14+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-125267

## Documents

- [advisory] Third-party advisory: www.vulncheck.com https://www.vulncheck.com/advisories/ffmpeg-before-8.1.3-and-9-x-before-9.0.2-heap-out-of-bounds-write-via-apac-decoder
- [fix] Patch: github.com https://github.com/FFmpeg/FFmpeg/commit/e15ddb7f9a2f9b3ab8ac305efb6f94ddc18463d0

## From the sources

FFmpeg before 8.1.3 and 9.x before 9.0.2 contains a heap out-of-bounds write vulnerability in the APAC decoder in libavcodec/apac.c caused by an unreset bitstream index. Attackers can supply a crafted APAC file whose growing bitstream_index triggers an integer overflow, bypassing the reallocation check so memcpy() corrupts heap memory or crashes the application.

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