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CVE Record

CVE-2021-28698: long running loops in grant table handling In order to properly monitor resource use, Xen maintains informa...

long running loops in grant table handling In order to properly monitor resource use, Xen maintains information on the grant mappings a domain may create to map grants offered by other domains. In the process of carrying out certain actions, Xen would iterate over all such entries, including ones which aren't in use anymore and some which may have been created but never used. If the number of entries for a given domain is large enough, this iterating of the entire table may tie up a CPU for too long, starving other domains or causing issues in the hypervisor itself. Note that a domain may map its own grants, i.e. there is no need for multiple domains to be involved here. A pair of "cooperating" guests may, however, cause the effects to be more severe.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysis

Security readout for executives and security teams

A guest VM on affected Xen hosts can make the hypervisor spend too long processing grant-table entries. That can tie up CPU time, degrade other VMs, or destabilize the hypervisor. This is primarily an availability risk for Xen-based virtualization environments. Exposure is likely limited to Xen hypervisors running affected xen versions listed in the bundle: 4.11.x, 4.12.x, 4.13.x, 4.14.x, 4.15.x, unspecified, or xen-unstable next. Risk is highest where tenants or less-trusted guest domains run on shared hosts. Treat this as a high-priority infrastructure availability issue if Xen supports production or customer workloads. It does not indicate data theft in the supplied sources, but a guest-triggered hypervisor slowdown can affect many services at once. Mitigation focus: Apply Xen XSA-380 guidance or patched packages from your distribution vendor.; Prioritize shared Xen hosts that run untrusted or multi-tenant guest domains.; Check Debian, Fedora, or Gentoo advisories if using their Xen packages..

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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

No CVSS vectors or timeline events were available in the normalized CVE source material.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
Xenxen4.14.xListed
Xenxenunspecified, 4.15.x, next of xen-unstableListed
Xenxen4.13.xListed
Xenxen4.11.xListed
Xenxen4.12.xListed
Weakness

CWE details

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