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             AUSCERT External Security Bulletin Redistribution

                     Citrix Hypervisor Security Update
                              5 February 2021


        AusCERT Security Bulletin Summary

Product:           Citrix Hypervisor
Publisher:         Citrix
Operating System:  Virtualisation
Impact/Access:     Denial of Service -- Existing Account
Resolution:        Patch/Upgrade
CVE Names:         CVE-2021-3308  

Original Bulletin: 

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Citrix Hypervisor Security Update

Reference: CTX291439
Category : Low
Created  : 02 February 2021
Modified : 04 February 2021

Applicable Products

  o Citrix Hypervisor

Description of Problem

A security issue has been identified that may allow privileged code running in
a guest VM to which a PCI passthrough device has been allocated to cause other
VMs with PCI passthrough devices to fail to boot, crash or become unresponsive.

This only applies to guest VMs where the host administrator has explicitly
allocated a host PCI device to the guest VM ("PCI Passthrough").

This issue has the following CVE identifier:

CVE ID        Description                       Vulnerability Pre-conditions
              An attacker with the ability to
              execute privileged code in a      CWE-664:      Administrator
              guest VM to which a PCI           Improper      access in guest
CVE-2021-3308 passthrough device has been       Control of a  to which a PCI
              allocated can cause other VMs     Resource      passthrough
              with PCI passthrough devices to   Through its   device has been
              fail to boot, crash or become     Lifetime      allocated

The only supported version of Citrix Hypervisor affected by this issue is 8.2

What Customers Should Do

Citrix has released a hotfix to address this issue. Citrix recommends that
affected customers install this hotfix as their patching schedule allows. The
hotfix can be downloaded from the following location:
Citrix Hypervisor 8.2 LTSR: CTX292625 - https://support.citrix.com/article/

Citrix is notifying customers and channel partners about this potential
security issue. This article is also available from the Citrix Knowledge Center
at . If you require technical assistance with this issue, please contact Citrix
Technical Support. Contact details for Citrix Technical Support are available
at . 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: - 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.


Date       Change
2021-02-04 Initial Publication

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