Citrix Hypervisor Security Update for CVE-2023-20593

Description of Problem

AMD has released updated microcode to address an issue with certain AMD CPUs. Although this is not an issue in the Citrix Hypervisor product itself, we have released a hotfix that includes this microcode to mitigate this CPU hardware issue.
This issue has the following identifier:

• CVE-2023-20593

Mitigating Factors

This issue only affects systems running Citrix Hypervisor when running on AMD Zen 2 CPUs; it does not affect Citrix Hypervisor when running on other supported CPUs.

What Customers Should Do

We have released a hotfix to address this issue in Citrix Hypervisor 8.2 LTSR CU1. We recommend that affected customers install this hotfix as soon as possible. The hotfix can be downloaded from the following location: <https://support.citrix.com/article/CTX569266&gt;

Note that the hotfix that originally addressed this security issue, XS82ECU1041, exposed a functional issue in Citrix Hypervisor when running on AMD Zen 2 CPUs. We have therefore withdrawn XS82ECU1041 as a standalone item and issued a new hotfix, XS82ECU1044, that addresses the functional issue and also addresses the security issue by including XS82ECU1041. We strongly recommend that customers using AMD Zen 2 CPUs who have previously applied XS82ECU1041 also apply XS82ECU1044, available from the link above.

What Citrix Is Doing

We are notifying customers and channel partners about this potential security issue through the publication of this security bulletin on the Citrix Knowledge Center at <https://support.citrix.com/securitybulletins&gt; .

Obtaining Support on This Issue

If you require technical assistance with this issue, please contact Citrix Technical Support. Contact details for Citrix Technical Support are available at <https://www.citrix.com/support/open-a-support-case&gt;.

Subscribe to Receive Alerts

Citrix strongly recommends that all customers subscribe to receive alerts when a Citrix security bulletin is created or modified at <https://support.citrix.com/user/alerts&gt;.

Reporting Security Vulnerabilities to Citrix

Citrix welcomes input regarding the security of its products and considers any and all potential vulnerabilities seriously. For details on our vulnerability response process and guidance on how to report security-related issues to Citrix, please see the following webpage: <https://www.citrix.com/about/trust-center/vulnerability-process.html&gt;.

Disclaimer

This document is provided on an “as is” basis and does not imply any kind of guarantee or warranty, including the warranties of merchantability or fitness for a particular use. Your use of the information on the document is at your own risk. Citrix reserves the right to change or update this document at any time. Customers are therefore recommended to always view the latest version of this document directly from the Citrix Knowledge Center.

Changelog