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CVE-2021-28694: IOMMU page mapping issues on x86 T[his CNA information record relates to multiple CVEs; the text explains w...

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).

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysis

Security readout for executives and security teams

CVE-2021-28694 affects Xen hypervisors on x86 systems where firmware defines memory regions that devices should access without IOMMU translation. Xen could let a guest undo or replace those mappings, creating a possible isolation failure between a guest and memory ranges it should not control. Exposure is most likely on x86 virtualization hosts running affected Xen versions, especially where ACPI tables define untranslated IOMMU regions. The source bundle does not identify cloud providers, appliances, or downstream products beyond Xen and distribution advisories. Treat this as a virtualization isolation risk needing prompt asset review and vendor patch tracking. Urgency is highest for Xen hosts running guest workloads on affected x86 versions, but the provided sources do not support claiming active exploitation. Mitigation focus: Check Xen Project XSA-378 for the applicable fix guidance.; Apply Xen updates from your distribution or vendor advisory.; Prioritize Xen 4.11.x through 4.15.x and xen-unstable hosts..

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Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
0Timeline events
0ADP providers
7Source links

CVSS and timeline data

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Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
Xenxen4.11.xListed
Xenxenxen-unstableListed
Xenxen4.12.xListed
Xenxen4.14.xListed
Xenxen4.15.xListed
Xenxen4.13.xListed
Weakness

CWE details

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