# What is CVE-2021-26311?

> CVE-2021-26311 is a high-severity flaw (CVSS 7.2) in Epyc 7232p from Amd, published on 13 May 2021. It is not on the list of flaws known to be exploited today. The latest forecast puts its chance of use in the next 30 days at 1.7%. If you run an affected version, plan in the vendor’s fix.

Canonical page: https://www.precursorintelligence.com/what-is/cve-2021-26311

## At a glance

- **Verdict:** Plan it in. No sign of exploitation and a low forecast. Patch it in your normal update cycle.
- **Precursor Intelligence risk score:** 48 out of 100 (Medium); action: Plan remediation. Kept up to date as the evidence changes.
- **Severity:** High (CVSS 7.2 out of 10)
- **Known to be exploited:** No, not on the list of flaws known to be exploited today
- **Chance of use in the next 30 days:** 1.7% (latest exploit-likelihood forecast)
- **Published:** 13 May 2021
- **Record last updated:** 25 May 2021
- **Main product:** Epyc 7232p from Amd
- **Affected products:** 65

## What is CVE-2021-26311? In plain terms

It can be attacked from anywhere on the internet with an administrator account, and nobody has to click anything. If it works, the attacker can read data, change data and take it offline.

### The 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.

### What kind of flaw is it?

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

### How an attack on it works

- Where an attacker can be: Anywhere on the internet
- How hard it is to pull off: Easy: no special conditions
- Login needed first: An administrator account
- Does someone have to click: No, nobody has to do anything
- What an attacker gets: Can read data, change data and take it offline

Severity vector: `CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H`

## Is CVE-2021-26311 being exploited? Not that we know of

It is not on the list of flaws known to be exploited today. The latest forecast puts the chance of it being used in the next 30 days at 1.7%. That can change at any time, which is why we keep watching.

Exploit likelihood over the last 7 days: 1.7%, 1.7%, 1.7%, 1.7%, 1.7%, 1.7%, 1.7%.

### Timeline

- 13 May 2021: Published
- 25 May 2021: Record last updated

### How Precursor Intelligence ranks it

CVE-2021-26311 scores **48 out of 100 (Medium)**, with the action "Plan remediation".

Every published flaw gets a risk score from 0 to 100, kept up to date as the evidence changes. Four things go into the score, from the one that counts most to the ones that count less:

- Evidence it is being exploited: biggest factor
- How severe it is: strong factor
- How widely exposed it is: smaller factor
- Threat activity around it: smaller factor

85 and above is Critical. Anything confirmed as exploited is always marked for an emergency patch, whatever its score. When this flaw matches software you track, it lands in your list with its score and the reasons behind it.

## Who is affected by CVE-2021-26311?

The published record lists 65 products.

- [Epyc 7232p](https://www.precursorintelligence.com/product/amd/epyc_7232p) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc 7251](https://www.precursorintelligence.com/product/amd/epyc_7251) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc 7252](https://www.precursorintelligence.com/product/amd/epyc_7252) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc 7261](https://www.precursorintelligence.com/product/amd/epyc_7261) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc 7262](https://www.precursorintelligence.com/product/amd/epyc_7262) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc 7272](https://www.precursorintelligence.com/product/amd/epyc_7272) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc 7281](https://www.precursorintelligence.com/product/amd/epyc_7281) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc 7282](https://www.precursorintelligence.com/product/amd/epyc_7282) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc 72f3](https://www.precursorintelligence.com/product/amd/epyc_72f3) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc 7301](https://www.precursorintelligence.com/product/amd/epyc_7301) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc 7302](https://www.precursorintelligence.com/product/amd/epyc_7302) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc 7302p](https://www.precursorintelligence.com/product/amd/epyc_7302p) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc 7313](https://www.precursorintelligence.com/product/amd/epyc_7313) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc 7313p](https://www.precursorintelligence.com/product/amd/epyc_7313p) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc 7343](https://www.precursorintelligence.com/product/amd/epyc_7343) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc 7351](https://www.precursorintelligence.com/product/amd/epyc_7351) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc 7351p](https://www.precursorintelligence.com/product/amd/epyc_7351p) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc 7352](https://www.precursorintelligence.com/product/amd/epyc_7352) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc 7371](https://www.precursorintelligence.com/product/amd/epyc_7371) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc 73f3](https://www.precursorintelligence.com/product/amd/epyc_73f3) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc 7401](https://www.precursorintelligence.com/product/amd/epyc_7401) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc 7401p](https://www.precursorintelligence.com/product/amd/epyc_7401p) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc 7402](https://www.precursorintelligence.com/product/amd/epyc_7402) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc 7402p](https://www.precursorintelligence.com/product/amd/epyc_7402p) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc 7413](https://www.precursorintelligence.com/product/amd/epyc_7413) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc 7443](https://www.precursorintelligence.com/product/amd/epyc_7443) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc 7443p](https://www.precursorintelligence.com/product/amd/epyc_7443p) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc 7451](https://www.precursorintelligence.com/product/amd/epyc_7451) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc 7452](https://www.precursorintelligence.com/product/amd/epyc_7452) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc 7453](https://www.precursorintelligence.com/product/amd/epyc_7453) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc 74f3](https://www.precursorintelligence.com/product/amd/epyc_74f3) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc 7501](https://www.precursorintelligence.com/product/amd/epyc_7501) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc 7502](https://www.precursorintelligence.com/product/amd/epyc_7502) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc 7502p](https://www.precursorintelligence.com/product/amd/epyc_7502p) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc 7513](https://www.precursorintelligence.com/product/amd/epyc_7513) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc 7532](https://www.precursorintelligence.com/product/amd/epyc_7532) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc 7542](https://www.precursorintelligence.com/product/amd/epyc_7542) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc 7543](https://www.precursorintelligence.com/product/amd/epyc_7543) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc 7543p](https://www.precursorintelligence.com/product/amd/epyc_7543p) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc 7551](https://www.precursorintelligence.com/product/amd/epyc_7551) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc 7551p](https://www.precursorintelligence.com/product/amd/epyc_7551p) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc 7552](https://www.precursorintelligence.com/product/amd/epyc_7552) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc 75f3](https://www.precursorintelligence.com/product/amd/epyc_75f3) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc 7601](https://www.precursorintelligence.com/product/amd/epyc_7601) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc 7642](https://www.precursorintelligence.com/product/amd/epyc_7642) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc 7643](https://www.precursorintelligence.com/product/amd/epyc_7643) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc 7662](https://www.precursorintelligence.com/product/amd/epyc_7662) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc 7663](https://www.precursorintelligence.com/product/amd/epyc_7663) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc 7702](https://www.precursorintelligence.com/product/amd/epyc_7702) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc 7702p](https://www.precursorintelligence.com/product/amd/epyc_7702p) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc 7713](https://www.precursorintelligence.com/product/amd/epyc_7713) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc 7713p](https://www.precursorintelligence.com/product/amd/epyc_7713p) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc 7742](https://www.precursorintelligence.com/product/amd/epyc_7742) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc 7763](https://www.precursorintelligence.com/product/amd/epyc_7763) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc 7f32](https://www.precursorintelligence.com/product/amd/epyc_7f32) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc 7f52](https://www.precursorintelligence.com/product/amd/epyc_7f52) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc 7f72](https://www.precursorintelligence.com/product/amd/epyc_7f72) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc 7h12](https://www.precursorintelligence.com/product/amd/epyc_7h12) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc Embedded 3101](https://www.precursorintelligence.com/product/amd/epyc_embedded_3101) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc Embedded 3151](https://www.precursorintelligence.com/product/amd/epyc_embedded_3151) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc Embedded 3201](https://www.precursorintelligence.com/product/amd/epyc_embedded_3201) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc Embedded 3251](https://www.precursorintelligence.com/product/amd/epyc_embedded_3251) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc Embedded 3255](https://www.precursorintelligence.com/product/amd/epyc_embedded_3255) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc Embedded 3351](https://www.precursorintelligence.com/product/amd/epyc_embedded_3351) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified
- [Epyc Embedded 3451](https://www.precursorintelligence.com/product/amd/epyc_embedded_3451) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified

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

1. **Check whether you run it.** Compare your versions with the affected products above. Not sure what you run? Precursor Intelligence can work it out from your public website, or you can pick it from a list.
2. **Apply the vendor’s fix.** Install the update named in the vendor’s advisory. We’ve put the advisory first in the list.
3. **If you can’t patch today.** Follow any mitigation the vendor publishes, and limit who can reach the affected system from the internet until the update is in.
4. **Keep an eye on it.** Track the product and we tell you as soon as we spot this flaw on the list of exploited flaws, or a jump in its exploit likelihood.

### References

- [amd.com](https://www.amd.com/en/corporate/product-security/bulletin/amd-sb-1004) (Vendor advisory)

## Questions

### What is CVE-2021-26311?

CVE-2021-26311 is a high-severity flaw in Epyc 7232p from Amd, published on 13 May 2021. It can be attacked from anywhere on the internet with an administrator account, and nobody has to click anything. If it works, the attacker can read data, change data and take it offline.

### How serious is CVE-2021-26311?

It scores 7.2 out of 10 on the CVSS severity scale, which is high. Our risk score for CVE-2021-26311 is 48 out of 100, which is Medium. Its action is "Plan remediation". No sign of exploitation and a low forecast. Patch it in your normal update cycle.

### Is CVE-2021-26311 being exploited?

It is not on the list of flaws known to be exploited today. The latest forecast puts the chance of it being used in the next 30 days at 1.7%. That can change at any time, which is why we keep watching.

### Which versions does CVE-2021-26311 affect?

For Epyc 7232p from Amd: version not specified. The record lists 65 products in all, each with its versions, under "Who is affected" on this page.

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

Install the update the vendor names in its advisory, linked first under "How do I fix" on this page. If you can't patch today, follow the vendor's mitigation and limit who can reach the affected system from the internet.

## Does CVE-2021-26311 affect you?

Precursor Intelligence keeps checking for you:

- **Tell us what you run.** Pick your software from a list, or let us work it out from your website.
- **We match it to every flaw.** Over 400,000 published flaws, checked against your list.
- **Ranked by real-world risk.** Every flaw gets a 0 to 100 risk score, kept up to date, led by evidence criminals are using it.
- **Told as soon as we know.** An alert by email, in the app or by webhook to your own tools.

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