---
id: "CVE-2025-55640"
kind: "vulnerability"
aliases: ["CVE-2025-55640"]
title: "GPAC MP4Box: crafted MP4 file triggers heap overflow and denial of service"
severity: "unknown"
cvss: null
epss: null
exploited: false
status: "open"
category: "other"
products: []
ecosystems: []
tags: ["gpac", "media-processing", "mp4box", "other"]
not_affected_if: ["no-untrusted-mp4-input"]
published_at: "2026-10-16T19:16:56+00:00"
first_seen_at: "2026-10-23T21:57:14+00:00"
updated_at: "2026-10-25T05:27:43+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-55640", "first_seen_at": "2026-10-23T21:57:14+00:00"}]
---

# GPAC MP4Box: crafted MP4 file triggers heap overflow and denial of service

GPAC MP4Box v2.4 has a heap buffer overflow in the stbl_AddSize function in isomedia/stbl_write.c. A crafted MP4 file can crash the tool, causing a 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 the fixed release (unknown from sources)
- Check whether MP4Box processes untrusted MP4 files, such as user uploads in a media pipeline

## Fix

- Upgrade GPAC MP4Box past `2.4` to a release that includes the fix (exact version unknown from sources)
- Until patched, do not run MP4Box on untrusted input

## Timeline

- 2026-10-23T21:57:14+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2025-55640

## From the sources

A heap buffer overflow in the stbl_AddSize function (isomedia/stbl_write.c) of GPAC MP4Box v2.4 allows attackers to cause a Denial of Service (DoS) via supplying a crafted MP4 file.

---

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