CVEvulnerability

CVE-2021-28695

6.8 MEDIUM Published 2021-08-27 Modified 2026-06-17 Official page ↗
Status
Modified
Published
2021-08-27
Last modified
2026-06-17
Assigner
[email protected]
CVSS 3.1 ([email protected])
6.8 MEDIUM — CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS 2.0 ([email protected])
4.6 MEDIUM — AV:L/AC:L/Au:N/C:P/I:P/A:P

Description

IOMMU page mapping issues on x86 T[his CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities correspond to which CVE.] Both AMD and Intel allow ACPI tables to specify regions of memory which should be left untranslated, which typically means these addresses should pass the translation phase unaltered. While these are typically device specific ACPI properties, they can also be specified to apply to a range of devices, or even all devices. On all systems with such regions Xen failed to prevent guests from undoing/replacing such mappings (CVE-2021-28694). On AMD systems, where a discontinuous range is specified by firmware, the supposedly-excluded middle range will also be identity-mapped (CVE-2021-28695). Further, on AMD systems, upon de-assigment of a physical device from a guest, the identity mappings would be left in place, allowing a guest continued access to ranges of memory which it shouldn't have access to anymore (CVE-2021-28696).

Affected configurations

• xen xen • fedoraproject fedora 33 • fedoraproject fedora 34 • fedoraproject fedora 35 • debian debian linux 10.0

References