CVE-2021-28695
First published: Fri Aug 27 2021(Updated: )
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).
Credit: security@xen.org
| Affected Software | Affected Version | How to fix |
|---|---|---|
| debian/xen | <=4.11.4+107-gef32c7afa2-1 | 4.14.6-1 4.14.5+94-ge49571868d-1 4.17.1+2-gb773c48e36-1 4.17.2+55-g0b56bed864-1 |
| Xen XAPI | ||
| Fedora | =33 | |
| Fedora | =34 | |
| Fedora | =35 | |
| Debian | =10.0 |
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Reference Links
- http://www.openwall.com/lists/oss-security/2021/09/01/1
- http://www.openwall.com/lists/oss-security/2021/09/01/5
- http://www.openwall.com/lists/oss-security/2021/09/01/6
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/2VQCFAPBNGBBAOMJZG6QBREOG5IIDZID/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/FZCNPSRPGFCQRYE2BI4D4Q4SCE56ANV2/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/LPRVHW4J4ZCPPOHZEWP5MOJT7XDGFFPJ/
- https://security.gentoo.org/glsa/202208-23
- https://www.debian.org/security/2021/dsa-4977
- https://xenbits.xenproject.org/xsa/advisory-378.txt
- https://xenbits.xen.org/xsa/advisory-378.html
- https://security-tracker.debian.org/tracker/CVE-2021-28695
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/LPRVHW4J4ZCPPOHZEWP5MOJT7XDGFFPJ/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FZCNPSRPGFCQRYE2BI4D4Q4SCE56ANV2/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2VQCFAPBNGBBAOMJZG6QBREOG5IIDZID/
Frequently Asked Questions
What is the severity of CVE-2021-28695?
CVE-2021-28695 is considered a high severity vulnerability affecting memory management in IOMMU configurations.
How do I fix CVE-2021-28695?
To fix CVE-2021-28695, upgrade to the recommended versions of the affected software listed, such as Xen versions 4.14.6-1 or higher.
What software is affected by CVE-2021-28695?
CVE-2021-28695 affects various versions of Xen and Debian, specifically those prior to 4.11.4+107-gef32c7afa2-1 for Xen.
What are the risks of not addressing CVE-2021-28695?
Failing to address CVE-2021-28695 may lead to unauthorized memory access or potential exploitation of virtual machine boundaries.
Is CVE-2021-28695 related to other vulnerabilities?
Yes, CVE-2021-28695 is associated with multiple CVEs regarding IOMMU page mapping issues in x86 architecture.
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