# CVE-2021-26321: Denial of service in 1st Gen AMD EPYC™

> A local authenticated attacker can cause a denial of service in the AMD PSP firmware due to insufficient command validation.

- **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:** No
- **Published:** 16 Nov 2021
- **Updated:** 16 Sep 2024
- **Also known as:** GHSA-f2xj-57vr-m78h

## What is CVE-2021-26321?

CVE-2021-26321 is a medium-severity denial of service vulnerability in Amd Epyc 7232p Firmware, published on 16 Nov 2021. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

Insufficient ID command validation in the SEV Firmware may allow a local authenticated attacker to perform a denial of service of the PSP.

Weakness: CWE-77 (Improper Neutralization of Special Elements used in a Command), CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2021-26321?

It affects 57 products.


Products: Amd Epyc 7232p Firmware, Amd Epyc 7251 Firmware, Amd Epyc 7252 Firmware, Amd Epyc 7261 Firmware, Amd Epyc 7262 Firmware, Amd Epyc 7272 Firmware, Amd Epyc 7281 Firmware, Amd Epyc 7282 Firmware, Amd Epyc 72f3 Firmware, Amd Epyc 7301 Firmware, Amd Epyc 7302 Firmware, Amd Epyc 7302p Firmware, Amd Epyc 7313 Firmware, Amd Epyc 7313p Firmware, Amd Epyc 7343 Firmware, Amd Epyc 7351 Firmware, Amd Epyc 7351p Firmware, Amd Epyc 7352 Firmware, Amd Epyc 7371 Firmware, Amd Epyc 73f3 Firmware and 37 more.

## How do I fix CVE-2021-26321?

No fix has been published for CVE-2021-26321 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-26321 being exploited?

There is no known exploitation of CVE-2021-26321 in the wild and no public exploit code.

## Other vulnerabilities in Amd Epyc 7232p Firmware

- [CVE-2021-26379](https://insights.sbomify.com/CVE-2021-26379/): Memory corruption in 2nd Gen AMD EPYC™ (critical 9.8)
- [CVE-2023-20520](https://insights.sbomify.com/CVE-2023-20520/): Memory corruption in 1st Gen AMD EPYC™ (critical 9.8)
- [CVE-2021-46756](https://insights.sbomify.com/CVE-2021-46756/): Denial of service in 1st Gen AMD EPYC™ Processors (critical 9.1)
- [CVE-2021-46769](https://insights.sbomify.com/CVE-2021-46769/): Other in 2nd Gen AMD EPYC™ (high 8.8)
- [CVE-2020-12944](https://insights.sbomify.com/CVE-2020-12944/): Memory corruption in Athlon™ Series (high 7.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-26321 and fix it if it is affected.

What it is: CVE-2021-26321 is a medium-severity denial of service vulnerability in Amd Epyc 7232p Firmware, published on 16 Nov 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-2021-26321 in the wild and no public exploit code.

Affected product: Amd Epyc 7232p Firmware. 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-2021-26321/ (Markdown: https://insights.sbomify.com/CVE-2021-26321/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-26321
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-26321
- OSV: https://osv.dev/vulnerability/CVE-2021-26321

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From sbomify Insights: https://insights.sbomify.com/CVE-2021-26321/
Summaries are generated and may contain mistakes; the official description above is the record.