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).
Published 2021-08-27 19:15:08
Updated 2022-09-28 19:56:58
Source Xen Project
View at NVD,   CVE.org

Exploit prediction scoring system (EPSS) score for CVE-2021-28695

Probability of exploitation activity in the next 30 days: 0.11%

Percentile, the proportion of vulnerabilities that are scored at or less: ~ 43 % EPSS Score History EPSS FAQ

CVSS scores for CVE-2021-28695

Base Score Base Severity CVSS Vector Exploitability Score Impact Score Score Source
4.6
MEDIUM AV:L/AC:L/Au:N/C:P/I:P/A:P
3.9
6.4
NIST
6.8
MEDIUM CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
0.9
5.9
NIST

References for CVE-2021-28695

Products affected by CVE-2021-28695

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