# CVE-2021-26409: Memory corruption in 3rd Gen EPYC

> Insufficient bounds checking in AMD SEV-ES allows attackers to corrupt Reverse Map table memory, compromising Secure Nested Paging integrity.

- **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:** 10 Jan 2023
- **Updated:** 9 Apr 2025
- **Also known as:** GHSA-53r6-9q9v-359p

## What is CVE-2021-26409?

CVE-2021-26409 is a high-severity memory corruption vulnerability in AMD 3rd Gen EPYC, 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

Insufficient bounds checking in SEV-ES may allow an attacker to corrupt Reverse Map table (RMP) memory, potentially resulting in a loss of SNP (Secure Nested Paging) memory integrity.

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

## Which versions are affected by CVE-2021-26409?

It affects 1 product.


Products: Amd Milanpi Firmware.

## How do I fix CVE-2021-26409?

No fix has been published for CVE-2021-26409 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-26409 being exploited?

There is no known exploitation of CVE-2021-26409 in the wild and no public exploit code.

## Other vulnerabilities in AMD 3rd Gen EPYC

- [CVE-2023-20522](https://insights.sbomify.com/CVE-2023-20522/): Denial of service in 2nd Gen EPYC (high 7.5)
- [CVE-2021-46779](https://insights.sbomify.com/CVE-2021-46779/): Memory corruption in 1st Gen EPYC (high 7.1)
- [CVE-2021-46767](https://insights.sbomify.com/CVE-2021-46767/): Other in 2nd Gen EPYC (medium 6.1)
- [CVE-2021-46768](https://insights.sbomify.com/CVE-2021-46768/): Denial of service in 2nd Gen EPYC (medium 5.5)
- [CVE-2021-46791](https://insights.sbomify.com/CVE-2021-46791/): Memory corruption in 3rd Gen EPYC (medium 5.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-26409 and fix it if it is affected.

What it is: CVE-2021-26409 is a high-severity memory corruption vulnerability in AMD 3rd Gen EPYC, 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-2021-26409 in the wild and no public exploit code.

Affected product: AMD 3rd Gen EPYC. 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-2021-26409/ (Markdown: https://insights.sbomify.com/CVE-2021-26409/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-26409
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-26409
- OSV: https://osv.dev/vulnerability/CVE-2021-26409

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-26409/
Summaries are generated and may contain mistakes; the official description above is the record.