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                            CERT-Renater

                Note d'Information No. 2026/VULN087
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DATE                : 27/01/2026

HARDWARE PLATFORM(S): /

OPERATING SYSTEM(S): Systems running XenServer versions 8.4.

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https://support.citrix.com/support-home/kbsearch/article?articleNumber=CTX695997&articleURL=XenServer_Security_Update_for_CVE_2025_58151_and_CVE_2026_23553
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XenServer Security Update for CVE-2025-58151 and CVE-2026-23553

Article Id : CTX695997
Last Modified Date : 01-27-2026 12:00
Created Date : 01-27-2026 10:16
Article Record Type : Security Bulletin
Severity : Medium


Summary

Severity: Medium 

Description of Problem  

An issue has been identified in XenServer 8.4 that may allow privileged
code in a guest VM to cause the host to become slow or unresponsive to
management operations. This issue has the following identifier:  

    CVE-2025-58151 

A further issue has been identified in XenServer 8.4 that may allow code
in a guest VM process to infer in-memory data of a different process
running within that same VM. This issue has the following identifier: 

    CVE-2026-23553 

Affected Versions  

These issues affect XenServer 8.4. 


Details

What Customers Should Do  

We have pushed updates to both the Early Access and Normal update channels
of XenServer 8.4.  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 


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/support-home/topic-article-list?trendingCategory=20&trendingTopicName=Security%20Bulletin 


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  

Citrix strongly recommends that all customers subscribe to receive alerts
when a security bulletin is created or modified at
https://support.citrix.com/wolken-support/view/aboutsupport/my-support-alerts 


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.cloud.com/trust-center/support  

Change Log
2026-01-27 	Initial Publication

 
Disclaimer

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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
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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
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Terms of Use.

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