CVE-2021-28695

CVE Details

Release Date:2021-08-27

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).

See more information about CVE-2021-28695 from MITRE CVE dictionary and NIST NVD


CVSS v3.0 metrics


NOTE: The following CVSS v3.0 metrics and score provided are preliminary and subject to review.

Base Score: 6.8 Base Metrics: AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Access Vector: Physical Attack Complexity: Low
Privileges Required: None User Interaction: None
Scope: Unchanged Confidentiality Impact: High
Integrity Impact: High Availability Impact: High

Errata information


PlatformErrataRelease Date
Oracle VM version 3 (xen)OVMSA-2021-00332021-10-07



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