# CVE-2026-4185: GPAC MP4Box swf_parse.c swf_def_bits_jpeg stack-based overflow

> A stack-based buffer overflow in GPAC's MP4Box allows remote attackers to execute arbitrary code or cause denial of service via crafted SWF files.

- **Severity:** Medium 5.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 15 Mar 2026
- **Updated:** 17 Mar 2026
- **Also known as:** DEBIAN-CVE-2026-4185, GHSA-2hwp-9jff-pr6q, UBUNTU-CVE-2026-4185

## What is CVE-2026-4185?

CVE-2026-4185 is a medium-severity memory corruption vulnerability in GPAC, published on 15 Mar 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

A vulnerability was found in GPAC up to 2.5-DEV-rev2167-gcc9d617c0-master. This vulnerability affects the function swf_def_bits_jpeg of the file src/scene_manager/swf_parse.c of the component MP4Box. The manipulation of the argument szName results in stack-based buffer overflow. It is possible to launch the attack remotely. The exploit has been made public and could be used. The patch is identified as 8961c74f87ae3fe2d3352e622f7730ca96d50cf1. A patch should be applied to remediate this issue.

Weakness: CWE-121 (Stack-based Buffer Overflow), CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer)

## Which versions are affected by CVE-2026-4185?


## How do I fix CVE-2026-4185?

No fix has been published for CVE-2026-4185 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-4185 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-4185 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-4185 and fix it if it is affected.

What it is: CVE-2026-4185 is a medium-severity memory corruption vulnerability in GPAC, published on 15 Mar 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-4185 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-2026-4185/ (Markdown: https://insights.sbomify.com/CVE-2026-4185/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-4185
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-4185
- OSV: https://osv.dev/vulnerability/CVE-2026-4185

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-4185/
Summaries are generated and may contain mistakes; the official description above is the record.