CVE Vulnerabilities

CVE-2021-28702

Improper Privilege Management

Published: Oct 06, 2021 | Modified: Nov 07, 2023
CVSS 3.x
7.6
HIGH
Source:
NVD
CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
CVSS 2.x
4.6 MEDIUM
AV:L/AC:L/Au:N/C:P/I:P/A:P
RedHat/V2
RedHat/V3
Ubuntu
MEDIUM

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.

Weakness

The product does not properly assign, modify, track, or check privileges for an actor, creating an unintended sphere of control for that actor.

Affected Software

Name Vendor Start Version End Version
Xen Xen 4.13.0 (including) 4.15.1 (including)
Xen Ubuntu bionic *
Xen Ubuntu hirsute *
Xen Ubuntu impish *
Xen Ubuntu kinetic *
Xen Ubuntu lunar *
Xen Ubuntu mantic *
Xen Ubuntu trusty *
Xen Ubuntu xenial *

Potential Mitigations

References