CVE-2021-28698 Information

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 ## CVSS Vector CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Reference

https://xenbits.xenproject.org/xsa/advisory-380.txt http://www.openwall.com/lists/oss-security/2021/09/01/2 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://www.debian.org/security/2021/dsa-4977 https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/2VQCFAPBNGBBAOMJZG6QBREOG5IIDZID/

Attack Complexity

LOW

Privileges Required

LOW

User Interaction Required

LOW

Scope

NONE

Confidentiality Impact

UNCHANGED

Integrity Impact

NONE

Availability Impact

NONE

Base Score

HIGH

Base Severity

5.5