# CVE-2021-38111: Memory corruption in n/a

> Remote attackers can exploit a buffer overflow in the DEF CON 27 badge via oversized NFMI packets to execute arbitrary code.

- **Severity:** High 8.8 (`CVSS:3.1/AV:A/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:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 4 Aug 2021
- **Updated:** 5 May 2025
- **Also known as:** GHSA-5jwm-jmmx-2mv2

## What is CVE-2021-38111?

CVE-2021-38111 is a high-severity memory corruption vulnerability in n/a, published on 4 Aug 2021. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

The DEF CON 27 badge allows remote attackers to exploit a buffer overflow by sending an oversized packet via the NFMI (Near Field Magnetic Induction) protocol.

Weakness: CWE-120 (Buffer Copy without Checking Size of Input)

## Which versions are affected by CVE-2021-38111?

It affects 1 product.


Products: Defcon Def Con 27 Firmware.

## How do I fix CVE-2021-38111?

No fix has been published for CVE-2021-38111 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-38111 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2021-38111 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-38111 and fix it if it is affected.

What it is: CVE-2021-38111 is a high-severity memory corruption vulnerability in n/a, published on 4 Aug 2021. 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-2021-38111 exists.

Affected product: n/a. 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-2021-38111/ (Markdown: https://insights.sbomify.com/CVE-2021-38111/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-38111
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-38111
- OSV: https://osv.dev/vulnerability/CVE-2021-38111

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-38111/
Summaries are generated and may contain mistakes; the official description above is the record.