Key points
- GPAC MP4Box versions prior to commit 4bbb6e5f7cb827e56f32b2f7a5918b0b8e395eb8 are affected by CVE-2025-55653.
- The vulnerability allows a local attacker to cause a denial of service by importing a crafted MP4 file.
- A fix has been identified in the upstream codebase, but no official binary release is confirmed yet.
Small-business owners using GPAC or its MP4Box tool for video processing should be aware of a newly disclosed security flaw. The issue, tracked as CVE-2025-55653, affects versions of the software prior to a specific code fix. According to the oss-security mailing list advisory posted on October 17, the vulnerability stems from how the application handles certain mathematical values within MP4 files.
In plain English
The problem occurs when MP4Box attempts to import a specially crafted MP4 file. This malicious file contains a fractional value with a zero denominator. When the software tries to process this invalid data, it attempts to divide by zero. This mathematical error causes the application to crash unexpectedly. The crash results in a loss of availability for the user, as the tool stops functioning until it is restarted.
The background
Alexander Shvedov, known online as @sigdevel, reported this issue to the oss-security mailing list. The advisory describes the flaw as a divide-by-zero error categorized under CWE-369. The Common Vulnerability Scoring System (CVSS) 3.1 rating for this vulnerability is 5.5, which is classified as medium severity. The attack vector is local, meaning the attacker must have some level of access to the system or the ability to get the user to open a crafted file.
What changes now
The fix for this issue is contained within a specific commit in the GPAC source code repository. The commit identifier is 4bbb6e5f7cb827e56f32b2f7a5918b0b8e395eb8. Users who compile GPAC from source can apply this fix by updating to this version or later. However, for users relying on pre-compiled binaries, it is unclear if a patched version has been released yet. Until an official update is confirmed, the risk remains for those processing untrusted MP4 files.
Who needs to act first
Teams should prioritize updating systems that process MP4 files from external or untrusted sources. If you handle customer-uploaded media, check whether your processing pipeline uses GPAC or MP4Box. Before applying any code changes, back up your current configuration and test the update in a non-production environment to ensure stability. If you cannot update immediately, restrict file uploads to trusted sources only. Consider implementing file validation tools that scan for malformed structures before they reach the processing engine. This reduces the chance of a crash occurring during normal operations.
What to do and how to stay safe: GPAC
- Verify if your current installation of GPAC or MP4Box is older than the fixed commit.
- Avoid opening MP4 files from unknown or untrusted senders until a patch is applied.
- Monitor vendor channels for an official binary release that includes the security fix.
- Once the vendor provides an update, test it thoroughly before deploying to production systems.
Step-by-step guide: Out-of-Band Patches: Meaning, Risks, and Deployment Reality
General security guidance from the Patch Herald newsroom. It is not confirmed advice from the organisations named in this story.
Frequently asked questions
What is the CVSS score for CVE-2025-55653?
The CVSS 3.1 score is 5.5, which is rated as medium severity.
Can this vulnerability be exploited remotely?
No, the attack vector is local, requiring the user to import a crafted file.
Is there an official patch available for download?
A fix exists in the source code, but no official binary release is confirmed in the advisory.
