# CVE-2026-90791: GPAC MP4Box base_scenegraph.c gf_node_unregister use after free

> A use-after-free vulnerability in GPAC MP4Box allows remote attackers to execute arbitrary code or cause denial of service via crafted media files.

- **Severity:** Medium 5.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P`)
- **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:** 14 Sep 2026
- **Updated:** 15 Sep 2026
- **Also known as:** GHSA-6x7f-5vmr-66vm, UBUNTU-CVE-2026-90791

## What is CVE-2026-90791?

CVE-2026-90791 is a medium-severity use after free vulnerability in GPAC, published on 14 Sep 2026. 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

A vulnerability was detected in GPAC up to f1219cde. This vulnerability affects the function gf_node_unregister of the file scenegraph/base_scenegraph.c of the component MP4Box. The manipulation results in use after free. The attack can be executed remotely. The exploit is now public and may be used. Upgrading to version abi-16.23 is able to resolve this issue. The patch is identified as 9eb40df4448b88d6a6ce3454657c06f47eff0b24. Upgrading the affected component is recommended.

Weakness: CWE-416 (Use After Free), CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer)

## Which versions are affected by CVE-2026-90791?


## How do I fix CVE-2026-90791?

No fix has been published for CVE-2026-90791 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-90791 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-90791 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-90791 and fix it if it is affected.

What it is: CVE-2026-90791 is a medium-severity use after free vulnerability in GPAC, published on 14 Sep 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-90791 exists.

Affected product: 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-2026-90791/ (Markdown: https://insights.sbomify.com/CVE-2026-90791/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-90791
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-90791
- OSV: https://osv.dev/vulnerability/CVE-2026-90791

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-90791/
Summaries are generated and may contain mistakes; the official description above is the record.