# CVE-2021-21862: Integer overflow in GPAC

> A crafted MPEG-4 file triggers an integer overflow in GPAC, leading to heap corruption and potential code execution when opened.

- **Severity:** High 8.8 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:R/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:** A user has to click or open something
- **Fix available:** No
- **Published:** 18 Aug 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-pcpx-9hrr-4ggq, UBUNTU-CVE-2021-21862

## What is CVE-2021-21862?

CVE-2021-21862 is a high-severity vulnerability in Gpac Gpac, published on 18 Aug 2021. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

Multiple exploitable integer truncation vulnerabilities exist within the MPEG-4 decoding functionality of the GPAC Project on Advanced Content library v1.0.1. A specially crafted MPEG-4 input can cause an improper memory allocation resulting in a heap-based buffer overflow that causes memory corruption The implementation of the parser used for the “Xtra” FOURCC code is handled. An attacker can convince a user to open a video to trigger this vulnerability.

Weakness: CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer), CWE-680 (Integer Overflow to Buffer Overflow)

## Which versions are affected by CVE-2021-21862?

It affects 1 product.


Products: Gpac Gpac.

## How do I fix CVE-2021-21862?

No fix has been published for CVE-2021-21862 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-21862 being exploited?

There is no known exploitation of CVE-2021-21862 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-2021-28300](https://insights.sbomify.com/CVE-2021-28300/): Null dereference 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)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-21862 and fix it if it is affected.

What it is: CVE-2021-21862 is a high-severity vulnerability in Gpac Gpac, published on 18 Aug 2021. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2021-21862 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-2021-21862/ (Markdown: https://insights.sbomify.com/CVE-2021-21862/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-21862
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-21862
- OSV: https://osv.dev/vulnerability/CVE-2021-21862

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-21862/
Summaries are generated and may contain mistakes; the official description above is the record.