CVE-2021-28698

Published Aug 27, 2021 CVSS 3.1 · 5.5 Medium EPSS < 1% KEV · Not listed
Description
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

Sign in to view the affected projects.

Advisories

Source ID Title
Debian DSA Debian DSA DSA-4977-1 xen security update
EUVD EUVD EUVD-2021-15355 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.
History

No history.

Weaknesses

Sources

Status
PUBLISHED
Assigner
XEN
Published
Updated
Aug 3, 2024, 9:47 PM
Reserved
Mar 18, 2021, 12:00 AM
Status
Modified
Published
Aug 27, 2021, 7:15 PM
Modified
Jun 17, 2026, 3:46 AM