# CVE-2021-26311: AMD Secure Encrypted Virtualization

> A malicious hypervisor can rearrange guest memory undetected by attestation, potentially leading to arbitrary code execution within the guest VM.

- **Severity:** High 7.2 (`CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 13 May 2021
- **Updated:** 17 Sep 2024
- **Also known as:** GHSA-2v8q-5wcx-2f5j

## What is CVE-2021-26311?

CVE-2021-26311 is a high-severity memory corruption vulnerability in AMD SEV/SEV-ES, published on 13 May 2021. An attacker needs administrator access to exploit it, with no action from the victim.

### Official description

In the AMD SEV/SEV-ES feature, memory can be rearranged in the guest address space that is not detected by the attestation mechanism which could be used by a malicious hypervisor to potentially lead to arbitrary code execution within the guest VM if a malicious administrator has access to compromise the server hypervisor.

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

## Which versions are affected by CVE-2021-26311?

It affects 65 products.


Products: Amd Epyc 7232p, Amd Epyc 7251, Amd Epyc 7252, Amd Epyc 7261, Amd Epyc 7262, Amd Epyc 7272, Amd Epyc 7281, Amd Epyc 7282, Amd Epyc 72f3, Amd Epyc 7301, Amd Epyc 7302, Amd Epyc 7302p, Amd Epyc 7313, Amd Epyc 7313p, Amd Epyc 7343, Amd Epyc 7351, Amd Epyc 7351p, Amd Epyc 7352, Amd Epyc 7371, Amd Epyc 73f3 and 45 more.

## How do I fix CVE-2021-26311?

No fix has been published for CVE-2021-26311 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-26311 being exploited?

There is no known exploitation of CVE-2021-26311 in the wild and no public exploit code.

## Other vulnerabilities in AMD SEV/SEV-ES

- [CVE-2020-12967](https://insights.sbomify.com/CVE-2020-12967/): AMD Secure Encrypted Virtualization (high 7.2)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-26311 and fix it if it is affected.

What it is: CVE-2021-26311 is a high-severity memory corruption vulnerability in AMD SEV/SEV-ES, published on 13 May 2021. An attacker needs administrator access to exploit it, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-26311 in the wild and no public exploit code.

Affected product: AMD SEV/SEV-ES. 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-2021-26311/ (Markdown: https://insights.sbomify.com/CVE-2021-26311/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-26311
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-26311
- OSV: https://osv.dev/vulnerability/CVE-2021-26311

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From sbomify Insights: https://insights.sbomify.com/CVE-2021-26311/
Summaries are generated and may contain mistakes; the official description above is the record.