CVE-2021-28696

 

Published at: - 27-08-2021 09:15

Last modified: - 28-09-2022 09:56

Total changes: - 11

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).

Common Vulnerability Scoring System (CVSS)

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

 

Verification logic

 

Reference

• https://xenbits.xenproject.org/xsa/advisory-378.txt
• [oss-security] 20210901 Xen Security Advisory 378 v3 (CVE-2021-28694,CVE-2021-28695,CVE-2021-28696) - IOMMU page mapping issues on x86-Mailing List, Third Party Advisory
• [oss-security] 20210901 Re: Xen Security Advisory 378 v3 (CVE-2021-28694,CVE-2021-28695,CVE-2021-28696) - IOMMU page mapping issues on x86-Mailing List, Third Party Advisory
• [oss-security] 20210901 Re: Xen Security Advisory 378 v3 (CVE-2021-28694,CVE-2021-28695,CVE-2021-28696) - IOMMU page mapping issues on x86-Mailing List, Third Party Advisory
• FEDORA-2021-d68ed12e46-Mailing List, Third Party Advisory
• FEDORA-2021-4f129cc0c1-Mailing List, Third Party Advisory
• DSA-4977-Third Party Advisory
• FEDORA-2021-081f9bf5d2-Mailing List, Third Party Advisory
• GLSA-202208-23-Third Party Advisory

 

Keywords

NVD

 

CVE-2021-28696

 

CVE

 

Common vulnerabilities & exposures

 

CVSS

 

Common vulnerability scoring system

 

Security

 

Vulnerabilities

 

Exposures