# CVE-2021-26331: Code injection in 1st Gen AMD EPYC™

> A malicious user can manipulate AMD SMU mailbox entries to achieve arbitrary code execution on EPYC processors.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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-945g-xqmp-7xg3

## What is CVE-2021-26331?

CVE-2021-26331 is a high-severity code injection 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

AMD System Management Unit (SMU) contains a potential issue where a malicious user may be able to manipulate mailbox entries leading to arbitrary code execution.

Weakness: CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2021-26331?

It affects 58 products.


Products: Amd Epyc 7001 Firmware, Amd Epyc 7002 Firmware, Amd Epyc 7003 Firmware, Amd Epyc 7232p Firmware, Amd Epyc 7251 Firmware, Amd Epyc 7252 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 and 38 more.

## How do I fix CVE-2021-26331?

No fix has been published for CVE-2021-26331 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-26331 being exploited?

There is no known exploitation of CVE-2021-26331 in the wild and no public exploit code.

## Other vulnerabilities in Amd Epyc 7232p Firmware

- [CVE-2021-26340](https://insights.sbomify.com/CVE-2021-26340/): A malicious hypervisor in conjunction with an unprivileged attacker process inside an SEV/SEV-ES guest VM may fail to flush the Translation (high 8.4)
- [CVE-2021-26398](https://insights.sbomify.com/CVE-2021-26398/): Memory corruption in 1st Gen EPYC (high 7.8)
- [CVE-2021-26335](https://insights.sbomify.com/CVE-2021-26335/): Code injection in Athlon™ Series (high 7.8)
- [CVE-2023-20578](https://insights.sbomify.com/CVE-2023-20578/): Race condition in AMD EPYC™ 7001 Processors (high 7.5)
- [CVE-2020-12988](https://insights.sbomify.com/CVE-2020-12988/): Denial of service in 1st/2nd/3rd Gen AMD EPYC™ Processors (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-26331 and fix it if it is affected.

What it is: CVE-2021-26331 is a high-severity code injection 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-2021-26331 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-2021-26331/ (Markdown: https://insights.sbomify.com/CVE-2021-26331/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-26331
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-26331
- OSV: https://osv.dev/vulnerability/CVE-2021-26331

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From sbomify Insights: https://insights.sbomify.com/CVE-2021-26331/
Summaries are generated and may contain mistakes; the official description above is the record.