# CVE-2021-26404: Information disclosure in 3rd Gen EPYC

> Improper input validation in AMD SEV firmware may leak scratch buffer bytes, potentially disclosing sensitive information to attackers.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N`)
- **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:** 10 Jan 2023
- **Updated:** 8 Apr 2025
- **Also known as:** GHSA-m5wf-22jj-7772

## What is CVE-2021-26404?

CVE-2021-26404 is a medium-severity vulnerability in Amd Epyc 7313 Firmware, published on 10 Jan 2023. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

Improper input validation and bounds checking in SEV firmware may leak scratch buffer bytes leading to potential information disclosure.

Weakness: CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2021-26404?

It affects 23 products.


Products: Amd Epyc 7003 Firmware, Amd Epyc 7313 Firmware, Amd Epyc 7313p Firmware, Amd Epyc 7343 Firmware, Amd Epyc 7373x Firmware, Amd Epyc 73f3 Firmware, Amd Epyc 7413 Firmware, Amd Epyc 7443 Firmware, Amd Epyc 7443p Firmware, Amd Epyc 7453 Firmware, Amd Epyc 7473x Firmware, Amd Epyc 74f3 Firmware, Amd Epyc 7513 Firmware, Amd Epyc 7543 Firmware, Amd Epyc 7543p Firmware, Amd Epyc 7573x Firmware, Amd Epyc 75f3 Firmware, Amd Epyc 7643 Firmware, Amd Epyc 7663 Firmware, Amd Epyc 7713 Firmware and 3 more.

## How do I fix CVE-2021-26404?

No fix has been published for CVE-2021-26404 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-26404 being exploited?

There is no known exploitation of CVE-2021-26404 in the wild and no public exploit code.

## Other vulnerabilities in Amd Epyc 7313 Firmware

- [CVE-2021-26315](https://insights.sbomify.com/CVE-2021-26315/): Code injection in 3rd Gen AMD EPYC™ (high 7.8)
- [CVE-2023-20530](https://insights.sbomify.com/CVE-2023-20530/): Denial of service in 3rd Gen EPYC (high 7.5)
- [CVE-2021-26343](https://insights.sbomify.com/CVE-2021-26343/): Information disclosure in 3rd Gen EPYC (medium 5.5)
- [CVE-2021-26355](https://insights.sbomify.com/CVE-2021-26355/): Denial of service in 3rd Gen EPYC (medium 5.5)
- [CVE-2021-26327](https://insights.sbomify.com/CVE-2021-26327/): Information disclosure in 3rd Gen AMD EPYC™ (medium 5.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-26404 and fix it if it is affected.

What it is: CVE-2021-26404 is a medium-severity vulnerability in Amd Epyc 7313 Firmware, published on 10 Jan 2023. 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-2021-26404 in the wild and no public exploit code.

Affected product: Amd Epyc 7313 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-2021-26404/ (Markdown: https://insights.sbomify.com/CVE-2021-26404/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-26404
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-26404
- OSV: https://osv.dev/vulnerability/CVE-2021-26404

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From sbomify Insights: https://insights.sbomify.com/CVE-2021-26404/
Summaries are generated and may contain mistakes; the official description above is the record.