Description of Problem

Intel has disclosed a security issue affecting Intel CPUs.  This CPU hardware issue may allow privileged code in a guest VM to infer some memory content of another VM that is running on the same CPU core.  Although this is not a vulnerability in the XenServer or Citrix Hypervisor products themselves, for the convenience of customers we are providing updates that contain updated Intel microcode and corresponding product code changes to mitigate this CPU hardware issue.

This issue has the following identifier:

• CVE-2024-28956

Affected Versions

This issue affects both XenServer 8.4 and Citrix Hypervisor 8.2CU1 LTSR.

Customers running Citrix Hypervisor 8.2CU1 are reminded that Citrix Hypervisor 8.2CU1 will become End of Life (EoL) on 25th June 2025 and that we recommend upgrading to XenServer 8.4 which is fully supported to 30th November 2028.

Mitigating Factors

Customers with deployments that do not contain Intel CPUs are not affected.

What Customers Should Do

• For customers using XenServer 8.4, we have pushed updates to both the Early Access and Normal update channels. We recommend that customers update to the latest version from their chosen channel following the instructions at https://docs.xenserver.com/en-us/xenserver/8/update 

• For customers using Citrix Hypervisor 8.2 CU1 LTSR, we have released a hotfix to address this issue. We recommend that customers install this hotfix and follow the instructions in the linked article. The hotfix can be downloaded from the following location:

  • CTX693229 - https://support.citrix.com/article/CTX693229  

What We Are 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. 

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.

Subscribe to Receive Alerts

We strongly recommend that all customers subscribe to receive alerts when a security bulletin is created or modified at https://support.citrix.com/user/alerts.

Reporting Security Vulnerabilities to Us

We welcome input regarding the security of our products and consider any and all potential vulnerabilities seriously. For details on our vulnerability response process and guidance on how to report security-related issues to us, please see the following webpage: https://www.cloud.com/trust-center/product-security/vulnerability-response.

Disclaimer 

The information on this page is being provided to you on an "AS IS" and "AS-AVAILABLE" basis. The issues described on this page may or may not impact your system(s). Cloud Software Group, Inc. and its subsidiaries (collectively, "Cloud SG") make no representations, warranties, or guarantees as to the information contained herein. ANY AND ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING, WITHOUT LIMITATION, INCLUDING, BUT NOT LIMITED TO, IMPLIED WARRANTIES OF MERCHANTABILITY, NON-INFRINGEMENT AND FITNESS FOR A PARTICULAR PURPOSE ARE HEREBY DISCLAIMED. BY ACCESSING THIS PAGE, YOU ACKNOWLEDGE THAT CLOUD SG SHALL IN NO EVENT BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, PUNITIVE, OR CONSEQUENTIAL DAMAGES THAT ARISE OUT OF YOUR USE OR FAILURE TO USE THE INFORMATION CONTAINED HEREIN. Cloud SG reserves the right to change or update the information on this page at any time. We accordingly recommend that you always view the latest version of this page. The information contained herein is being provided to you under the terms of your applicable customer agreement with Cloud SG, and may be used only for the purposes contemplated by such agreement. If you do not have such an agreement with Cloud SG, this information is provided under the cloud.com Terms of Use, and may be used only for the purposes contemplated by such Terms of Use.

Change log