---
title: "CVE-2021-28702\n    | Ubuntu"
description: Ubuntu is an open source software operating system that runs from the
  desktop, to the cloud, to all your internet connected things.
url: https://ubuntu.com/security/CVE-2021-28702?format=md
keywords: index, follow
---

# CVE-2021-28702

Publication date 6 October 2021

Last updated 11 July 2025

---

Ubuntu priority

**Medium**

[Why this priority?](https://ubuntu.com/security/cves/about#priority )

## Cvss 3 Severity Score

**7.6 · High**

[Score breakdown](https://ubuntu.com/security/CVE-2021-28702?format=md#impact-score)

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## Description

PCI devices with RMRRs not deassigned correctly Certain PCI devices in a
system might be assigned Reserved Memory Regions (specified via Reserved
Memory Region Reporting, "RMRR"). These are typically used for platform
tasks such as legacy USB emulation. If such a device is passed through to a
guest, then on guest shutdown the device is not properly deassigned. The
IOMMU configuration for these devices which are not properly deassigned
ends up pointing to a freed data structure, including the IO Pagetables.
Subsequent DMA or interrupts from the device will have unpredictable
behaviour, ranging from IOMMU faults to memory corruption.

[Read the notes from the security team](https://ubuntu.com/security/CVE-2021-28702?format=md#notes)

## Status

Show unmaintained releases

| Package | Ubuntu Release | Status |
| --- | --- | --- |
| xen | 26.04 LTS resolute | Needs evaluation |
| 25.10 questing | Ignored end of life, was needs-triage |
| 25.04 plucky | Ignored end of life, was needs-triage |
| 24.10 oracular | Ignored end of life, was needs-triage |
| 24.04 LTS noble | Needs evaluation |
| 23.10 mantic | Ignored end of life, was needs-triage |
| 23.04 lunar | Ignored end of life, was needs-triage |
| 22.10 kinetic | Ignored end of life, was needs-triage |
| 22.04 LTS jammy | Needs evaluation |
| 21.10 impish | Ignored end of life |
| 21.04 hirsute | Ignored end of life |
| 20.04 LTS focal | Needs evaluation |
| 18.04 LTS bionic | Needs evaluation |
| 16.04 LTS xenial | Needs evaluation |
| 14.04 LTS trusty | Not in release |

---

* [How can I get the fixes?](https://ubuntu.com/security/cves/about#security)
* [What do statuses mean?](https://ubuntu.com/security/cves/about#statuses)

## Notes

---

### [mdeslaur](https://launchpad.net/~mdeslaur)

hypervisor packages are in universe. For
issues in the hypervisor, add appropriate
tags to each section, ex:
Tags\_xen: universe-binary

## Severity score breakdown

CVSS version:
CVSS v3.0

**Base score**

7.6 · High

* Base metrics

  | Parameter | Value |
  | --- | --- |
  | Attack vector | Physical |
  | Attack complexity | Low |
  | Privileges required | None |
  | User interaction | None |
  | Scope | Changed |
  | Confidentiality impact | High |
  | Integrity impact | High |
  | Availability impact | High |
* Scores

  | Parameter | Value |
  | --- | --- |
  | Base score | 7.6 · High |
  | Exploitability score | - |
  | Impact score | - |

**Vector:** CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

## References

* [MITRE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-28702)
* [NVD](https://nvd.nist.gov/vuln/detail/CVE-2021-28702)
* [Launchpad](https://launchpad.net/bugs/cve/CVE-2021-28702)
* [Debian](https://security-tracker.debian.org/tracker/CVE-2021-28702)

### Other references

* <https://xenbits.xen.org/xsa/advisory-386.html>
* <https://xenbits.xenproject.org/xsa/advisory-386.txt>
* <https://www.cve.org/CVERecord?id=CVE-2021-28702>