# CVE-2021-38206: Null dereference in n/a

> Attackers can cause a denial of service in the Linux kernel by injecting specific 802.11a frames on 5 GHz-only devices.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 8 Aug 2021
- **Updated:** 8 Oct 2026
- **Also known as:** AZL-6590, DEBIAN-CVE-2021-38206, GHSA-pmfg-qv3m-chqh, UBUNTU-CVE-2021-38206

## What is CVE-2021-38206?

CVE-2021-38206 is a medium-severity vulnerability in Linux kernel, published on 8 Aug 2021. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

The mac80211 subsystem in the Linux kernel before 5.12.13, when a device supporting only 5 GHz is used, allows attackers to cause a denial of service (NULL pointer dereference in the radiotap parser) by injecting a frame with 802.11a rates.

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2021-38206?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2021-38206?

Upgrade to a fixed version.

## Is CVE-2021-38206 being exploited?

There is no known exploitation of CVE-2021-38206 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-38206 and fix it if it is affected.

What it is: CVE-2021-38206 is a medium-severity vulnerability in Linux kernel, published on 8 Aug 2021. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-38206 in the wild and no public exploit code.

Affected product: Linux kernel. 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-2021-38206/ (Markdown: https://insights.sbomify.com/CVE-2021-38206/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-38206
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-38206
- OSV: https://osv.dev/vulnerability/CVE-2021-38206

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-38206/
Summaries are generated and may contain mistakes; the official description above is the record.