# CVE-2021-28300: Null dereference in n/a

> Attackers can execute arbitrary code or cause denial of service by uploading a malicious MP4 file to applications using the GPAC library.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 14 Apr 2021
- **Updated:** 3 Aug 2024
- **Also known as:** DEBIAN-CVE-2021-28300, GHSA-5wqc-3hgv-x49w, UBUNTU-CVE-2021-28300

## What is CVE-2021-28300?

CVE-2021-28300 is a critical vulnerability in Gpac Gpac, published on 14 Apr 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

NULL Pointer Dereference in the "isomedia/track.c" module's "MergeTrack()" function of GPAC v0.5.2 allows attackers to execute arbitrary code or cause a Denial-of-Service (DoS) by uploading a malicious MP4 file.

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2021-28300?

It affects 1 product.


Products: Gpac Gpac.

## How do I fix CVE-2021-28300?

Upgrade to a fixed version.

## Is CVE-2021-28300 being exploited?

There is no known exploitation of CVE-2021-28300 in the wild and no public exploit code.

## Other vulnerabilities in Gpac Gpac

- [CVE-2023-46427](https://insights.sbomify.com/CVE-2023-46427/): Null dereference in n/a (critical 9.8)
- [CVE-2023-46932](https://insights.sbomify.com/CVE-2023-46932/): Memory corruption in n/a (critical 9.8)
- [CVE-2022-36190](https://insights.sbomify.com/CVE-2022-36190/): Use after free in n/a (critical 9.8)
- [CVE-2020-11558](https://insights.sbomify.com/CVE-2020-11558/): Use after free in n/a (critical 9.8)
- [CVE-2020-19751](https://insights.sbomify.com/CVE-2020-19751/): Memory corruption in n/a (critical 9.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-28300 and fix it if it is affected.

What it is: CVE-2021-28300 is a critical vulnerability in Gpac Gpac, published on 14 Apr 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-28300 in the wild and no public exploit code.

Affected product: Gpac Gpac. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2021-28300/ (Markdown: https://insights.sbomify.com/CVE-2021-28300/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-28300
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-28300
- OSV: https://osv.dev/vulnerability/CVE-2021-28300

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-28300/
Summaries are generated and may contain mistakes; the official description above is the record.