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             AUSCERT External Security Bulletin Redistribution

                     Citrix Hypervisor Security Update
                              21 January 2021


        AusCERT Security Bulletin Summary

Product:           Citrix Hypervisor
Publisher:         Citrix
Operating System:  Network Appliance
Impact/Access:     Execute Arbitrary Code/Commands -- Existing Account
Resolution:        Patch/Upgrade
CVE Names:         CVE-2020-29040  

Original Bulletin: 

Revision History:  January  21 2021: Vendor updated with CVE ID
                   November 25 2020: Initial Release

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Citrix Hypervisor Security Update

Reference: CTX286511
Category : Medium
Created  : 24 November 2020
Modified : 20 January 2021

Applicable Products

  o Citrix Hypervisor
  o XenServer

Description of Problem

A security issue has been identified that may allow privileged code running in
a guest VM to compromise the host. This issue is limited to only those guest
VMs where the host administrator has explicitly assigned a PCI passthrough
device to the guest VM.

The issue has the following identifier:

CVE ID         Description           Vulnerability Pre-conditions
CVE-2020-29040 Bounding error        CWE-121       A PCI passthrough device
               updating physmap                    must be assigned

This issue affects all currently supported versions of Citrix Hypervisor up to
and including Citrix Hypervisor 8.2 LTSR.

Mitigating Factors

Customers who are not using the PCI passthrough feature of Citrix Hypervisor
are not at risk from this issue

What Customers Should Do

Citrix has released hotfixes to address this issue. Citrix recommends that
affected customers install these hotfixes as their patching schedule allows.
The hotfixes can be downloaded from the following locations:
Citrix Hypervisor 8.2 LTSR: CTX286459 - https://support.citrix.com/article/
Citrix Hypervisor 8.1: CTX286458 - https://support.citrix.com/article/CTX286458
Citrix XenServer 7.1 LTSR CU2: CTX286457 - https://support.citrix.com/article/
Citrix XenServer 7.0: CTX286456 - https://support.citrix.com/article/CTX286456


Date       Change
2020-11-24 Initial Publication
2021-01-20 CVE ID Added

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