CVE-2025-55652: Heap Buffer Overflow in GPAC MP4Box v2.4 – DoS Vulnerability

Technical summary

CVE-2025-55652 is a heap buffer overflow vulnerability in the gf_isom_vp_config_new function within isomedia/avc_ext.c of GPAC MP4Box v2.4. The vulnerability arises from improper bounds checking when processing video codec configuration structures embedded in MP4 container files. When a crafted MP4 file with malformed codec configuration data is parsed, the function writes beyond allocated heap memory, corrupting adjacent data structures. This corruption leads to application crash and denial of service. The vulnerability is classified as CWE-122 (Heap-based Buffer Overflow).

Business impact

For organizations using GPAC MP4Box in automated media processing pipelines, this vulnerability introduces a denial-of-service vector that could disrupt video transcoding, streaming preparation, or media analysis workflows. If MP4Box is exposed through a web service or integrated into user-facing applications that accept media uploads, an attacker could submit crafted files to crash the service or consume resources. The impact is primarily availability-focused, with no data breach or system compromise risk, but downtime in media processing infrastructure can have cascading effects on content delivery operations.

Affected systems

GPAC MP4Box version 2.4 is confirmed vulnerable. Organizations should verify whether they are using this specific version in development environments, production media servers, transcoding infrastructure, or embedded within other applications. The vulnerability requires local or network-based file access to trigger; it cannot be exploited remotely without a vector to deliver the crafted MP4 file to a vulnerable instance.

Exploitability

Exploitation requires user interaction or application design that processes untrusted MP4 files. The attack surface depends on deployment context: media processing services accepting user uploads, automated content analysis pipelines, or desktop applications handling media files are primary targets. An attacker must craft a specific MP4 file that triggers the buffer overflow, which is technically feasible but not trivial. No public exploit code is known to exist. The CVSS score of 5.5 (Medium severity) reflects the requirement for user interaction and the availability-only impact.

Remediation

Immediate action: upgrade GPAC to a patched version released after this vulnerability disclosure. Verify the patch version number against the official GPAC release notes and security advisories. Interim mitigation: restrict MP4Box processing to trusted file sources, disable media file uploads from untrusted users, run MP4Box with minimal privileges, and isolate it in containerized or sandboxed environments to limit crash impact. Input validation is difficult to apply at the application level due to the complexity of MP4 format parsing.

Patch guidance

Contact GPAC maintainers and monitor their official repository and security advisory channels for patch releases. When a patched version becomes available, test it thoroughly in a staging environment before production deployment, especially for critical media processing pipelines. Document the upgrade process for all systems and services running MP4Box v2.4. Consider implementing automated dependency scanning to catch future updates.

Detection guidance

Monitor application logs and system journals for MP4Box crashes, particularly when processing media files from external sources. Implement file integrity monitoring on media input directories to detect unexpected file modifications. Network-based detection is limited; focus on endpoint-level indicators such as unexpected process termination, resource exhaustion, or core dumps. If MP4Box is containerized, monitor container restart rates as a signal of repeated crashes. Security teams should also audit media processing workflows to identify which systems accept user-supplied MP4 files.

Why prioritize this

While the CVSS score is Medium (5.5), prioritization depends on your organization's media processing infrastructure footprint. Prioritize patching if MP4Box is used in production transcoding, streaming preparation, or any internet-facing service accepting media uploads. Lower priority if MP4Box usage is isolated to offline content analysis or development-only environments. The lack of KEV status and absence of known public exploits reduce urgency compared to actively exploited vulnerabilities, but the ease of triggering via file upload warrants timely patching within a standard maintenance window.

Risk score, explained

The CVSS v3.1 score of 5.5 (Medium) reflects: local attack vector (file must be opened locally or delivered to a service), low attack complexity, no special privileges required, user interaction needed (opening/processing the file), and high impact on availability (denial of service via crash). The score appropriately discounts this from High severity because there is no confidentiality or integrity impact and exploitation requires file delivery. For organizations with high-volume media processing, the practical risk may warrant treating it as higher priority despite the CVSS rating.

Frequently asked questions