CVE-2021-28696
6.8 · MEDIUMOverview
CVE-2021-28696 is a medium-severity vulnerability affecting xen xen. It was published on August 27, 2021 and has a CVSS 3.1 base score of 6.8 (MEDIUM).
This vulnerability has a CVSS 3.1 base score of 6.8, rated MEDIUM. It requires local or adjacent network access to exploit. No authentication or special privileges are required for exploitation.
Technical 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).
Remediation
Check the references section for vendor advisories and patches from xen. Update xen to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
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References
Frequently Asked Questions
What is CVE-2021-28696?
CVE-2021-28696 is a medium-severity vulnerability affecting xen xen. It was published on August 27, 2021 and has a CVSS 3.1 base score of 6.8 (MEDIUM).
How severe is CVE-2021-28696?
This vulnerability has a CVSS 3.1 base score of 6.8, rated MEDIUM. It requires local or adjacent network access to exploit. No authentication or special privileges are required for exploitation.
How do I fix or remediate CVE-2021-28696?
Check the references section for vendor advisories and patches from xen. Update xen to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2021-28696?
CyberStrike's AI-powered security agents can automatically detect CVE-2021-28696 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
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