CVE-2021-28702 Information

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.

CVSS Vector

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

Reference

https://xenbits.xenproject.org/xsa/advisory-386.txt http://www.openwall.com/lists/oss-security/2021/10/07/2 https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/FDPRMOBBLS74ONYP3IXZZXSTLKR7GRQB/ https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/TRAWV6PO2KUGVZTESERECOBUBZ6X45I7/ https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/2OIHEJ3R3EH5DYI2I5UMD2ULJ2ELA3EX/ https://www.debian.org/security/2021/dsa-5017

Attack Complexity

LOW

Privileges Required

NONE

User Interaction Required

NONE

Scope

NONE

Confidentiality Impact

CHANGED

Integrity Impact

HIGH

Availability Impact

HIGH

Base Score

HIGH

Base Severity

7.6