CVE-2021-28696
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 | =11.0 |
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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-2021-28696
- 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-2021-28696?
CVE-2021-28696 has a high severity rating due to potential security risks associated with IOMMU page mapping issues.
How do I fix CVE-2021-28696?
To fix CVE-2021-28696, you should update to affected package versions indicated in the remediation details.
Which software is affected by CVE-2021-28696?
CVE-2021-28696 affects multiple versions of Xen and related operating systems including Debian and Fedora.
What types of vulnerabilities does CVE-2021-28696 address?
CVE-2021-28696 addresses IOMMU page mapping issues that can lead to unauthorized memory access.
Are there any specific distributions affected by CVE-2021-28696?
Yes, Debian 11.0 and Fedora versions 33, 34, and 35 are specifically affected by CVE-2021-28696.
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