CVE-2021-28697

Severity CVSS v4.0:

Pending analysis

Type:

CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

Publication date:

27/08/2021

Last modified:

07/11/2023

Description

grant table v2 status pages may remain accessible after de-allocation Guest get permitted access to certain Xen-owned pages of memory. The majority of such pages remain allocated / associated with a guest for its entire lifetime. Grant table v2 status pages, however, get de-allocated when a guest switched (back) from v2 to v1. The freeing of such pages requires that the hypervisor know where in the guest these pages were mapped. The hypervisor tracks only one use within guest space, but racing requests from the guest to insert mappings of these pages may result in any of them to become mapped in multiple locations. Upon switching back from v2 to v1, the guest would then retain access to a page that was freed and perhaps re-used for other purposes.

Impact

Vector 3.x

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H CVSS v3.1 Severity and Metrics:

Base Score: 7.80 HIGH
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Attack Vector (AV): Local
Attack Complexity (AC): Low
Privileges Required (PR): Low
User Interaction (UI): None
Scope (S): Unchanged
Confidentiality (C): High
Integrity (I): High
Availability (A): High

Base Score 3.x

7.80

Severity 3.x

HIGH

Vector 2.0

AV:L/AC:L/Au:N/C:P/I:P/A:P CVSS v2.0 Severity and Metrics:

Base Score: 4.60 MEDIUM
Vector: AV:L/AC:L/Au:N/C:P/I:P/A:P

Attack Vector (AV): Local
Attack Complexity (AC): Low
Authentication (Au): None
Confidentiality (C): Physical
Integrity (I): Physical
Availability (A): Physical

Base Score 2.0

4.60

Severity 2.0

MEDIUM

Vulnerable products and versions

CPE	From	Up to
cpe:2.3:o:xen:xen::::::::	4.0.0 (including)	4.15.0 (including)
cpe:2.3:o:fedoraproject:fedora:33:::::::*
cpe:2.3:o:fedoraproject:fedora:34:::::::*
cpe:2.3:o:fedoraproject:fedora:35:::::::*
cpe:2.3:o:debian:debian_linux:11.0:::::::*

To consult the complete list of CPE names with products and versions, see this page

CVE-2021-28697

Description

Impact

Vulnerable products and versions

References to Advisories, Solutions, and Tools