---
id: "CVE-2025-71438"
kind: "vulnerability"
aliases: ["CVE-2025-71438"]
title: "GPAC MP4Box: crafted AC4 file triggers out-of-bounds read, crashing the tool"
severity: "low"
cvss: null
epss: 0.00164
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["gpac", "media-processing", "mp4box", "package"]
not_affected_if: ["mp4box-not-used", "trusted-input-only"]
published_at: "2026-10-21T14:17:07+00:00"
first_seen_at: "2026-10-23T21:57:28+00:00"
updated_at: "2026-10-25T05:02:13+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-71438", "first_seen_at": "2026-10-23T21:57:28+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2025-71438", "first_seen_at": "2026-10-24T13:15:54+00:00"}]
---

# GPAC MP4Box: crafted AC4 file triggers out-of-bounds read, crashing the tool

GPAC's MP4Box tool reads past the end of a buffer while parsing AC4 audio configuration data in its descriptor code. An attacker who supplies a crafted AC4 file can crash the process, causing denial of service.

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

## How to check

- Run `MP4Box -version` and compare against `v26.07.0`
- Check whether MP4Box is used to process untrusted AC4 or MP4 files, for example in an upload or transcoding pipeline

## Fix

- Upgrade GPAC to `v26.07.0` or later

## Timeline

- 2026-10-23T21:57:28+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2025-71438
- 2026-10-24T13:15:54+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2025-71438

## From the sources

An out-of-bounds read in gf_odf_ac4_cfg_dsi_v1 (/odf/descriptors.c) in GPAC Project/MP4Box before v26.07.0 allows attackers to cause a Denial of Service (DoS) via supplying a crafted AC4 file.

---

_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_