# CVE-2016-20039: Multi Emulator Super System 0.154-3.1 Buffer Overflow

> Local attackers can execute arbitrary code or crash the application by supplying an oversized gamma parameter value.

- **Severity:** High 8.6 (`CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 28 Mar 2026
- **Updated:** 30 Mar 2026
- **Also known as:** GHSA-8vxc-wffq-wgmw

## What is CVE-2016-20039?

CVE-2016-20039 is a high-severity memory corruption vulnerability in mamedev Mess Emulator, published on 28 Mar 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

Multi Emulator Super System 0.154-3.1 contains a buffer overflow vulnerability in the gamma parameter handling that allows local attackers to crash the application or execute arbitrary code. Attackers can supply an oversized gamma parameter value to overflow the stack buffer and overwrite the instruction pointer with a controlled address to achieve code execution.

Weakness: CWE-787 (Out-of-bounds Write)

## Which versions are affected by CVE-2016-20039?


## How do I fix CVE-2016-20039?

No fix has been published for CVE-2016-20039 yet. Limit exposure of the affected software until one is available.

## Is CVE-2016-20039 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2016-20039 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2016-20039 and fix it if it is affected.

What it is: CVE-2016-20039 is a high-severity memory corruption vulnerability in mamedev Mess Emulator, published on 28 Mar 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2016-20039 exists.

Affected product: mamedev Mess Emulator. 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-2016-20039/ (Markdown: https://insights.sbomify.com/CVE-2016-20039/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2016-20039
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2016-20039
- OSV: https://osv.dev/vulnerability/CVE-2016-20039

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From sbomify Insights: https://insights.sbomify.com/CVE-2016-20039/
Summaries are generated and may contain mistakes; the official description above is the record.