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CVE-2021-28698

5.5 · MEDIUM

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.

Published Aug 27, 2021CWE-835EPSS 0.35%

Overview

CVE-2021-28698 is a medium-severity vulnerability. It was published on August 27, 2021 and has a CVSS 3.1 base score of 5.5 (MEDIUM).

This vulnerability has a CVSS 3.1 base score of 5.5, rated MEDIUM. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.

Technical 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

Check the references section for vendor advisories, patches, and mitigation guidance. 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.

References

Refwww.openwall.com/lists/oss-security/2021/09/01/2Reflists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2VQCFAPBNGBBAOMJZG6QBREOG5IIDZID/Reflists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FZCNPSRPGFCQRYE2BI4D4Q4SCE56ANV2/Reflists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/LPRVHW4J4ZCPPOHZEWP5MOJT7XDGFFPJ/Refsecurity.gentoo.org/glsa/202208-23Refwww.debian.org/security/2021/dsa-4977Refxenbits.xenproject.org/xsa/advisory-380.txtRefwww.openwall.com/lists/oss-security/2021/09/01/2Reflists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2VQCFAPBNGBBAOMJZG6QBREOG5IIDZID/Reflists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FZCNPSRPGFCQRYE2BI4D4Q4SCE56ANV2/

How CyberStrike helps

Frequently asked questions

What is CVE-2021-28698?

CVE-2021-28698 is a medium-severity vulnerability. It was published on August 27, 2021 and has a CVSS 3.1 base score of 5.5 (MEDIUM).

How severe is CVE-2021-28698?

This vulnerability has a CVSS 3.1 base score of 5.5, rated MEDIUM. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.

How do I fix or remediate CVE-2021-28698?

Check the references section for vendor advisories, patches, and mitigation guidance. 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-2021-28698?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2021-28698 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.

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