Hash: SHA256

             AUSCERT External Security Bulletin Redistribution

             CVE-2016-9603 - Citrix XenServer Security Update
                               18 July 2023


        AusCERT Security Bulletin Summary

Product:           Citrix XenServer
Publisher:         Citrix
Operating System:  Citrix XenServer
Resolution:        Patch/Upgrade
CVE Names:         CVE-2016-9603  

Original Bulletin: 

Comment: CVSS (Max):  9.9 CVE-2016-9603 (CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H)
         CVSS Source: NVD
         Calculator:  https://www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

- --------------------------BEGIN INCLUDED TEXT--------------------

CVE-2016-9603 - Citrix XenServer Security Update

Reference: CTX221578
Category : Severity: High
Created  : 14 March 2017
Modified : 15 August 2019

Applicable Products

  o XenServer 7.1

Description of Problem

A security issue has been identified within Citrix XenServer. This issue could,
if exploited, allow the administrator of an HVM guest VM to compromise the

The following vulnerability has been addressed:

  o CVE-2016-9603 (High): QEMU: Cirrus VGA Heap overflow via display refresh

Mitigating Factors

Customers using only PV guest VMs are not affected by this vulnerability.

Customers using only VMs that use the std-vga graphics emulation are not
affected by this vulnerability.

What Customers Should Do

Hotfixes have been released to address these issues. Citrix recommends that
affected customers install these hotfixes, which can be downloaded from the
following locations:

Citrix XenServer 7.1: CTX221590 - https://support.citrix.com/article/CTX221590

Citrix XenServer 7.0: CTX221571 - https://support.citrix.com/article/CTX221571

Citrix XenServer 6.5 SP1: CTX221716 - https://support.citrix.com/article/

Citrix XenServer 6.2 SP1: CTX221569 - https://support.citrix.com/article/

Citrix XenServer 6.0.2 Common Criteria: CTX221568- https://support.citrix.com/

What Citrix Is Doing

Citrix is notifying customers and channel partners about this potential
security issue. This article is also available from the Citrix Knowledge Center
at http://support.citrix.com/ .

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.html .

Reporting Security Vulnerabilities

Citrix welcomes input regarding the security of its products and considers any
and all potential vulnerabilities seriously. For guidance on how to report
security-related issues to Citrix, please see the following document: CTX081743
- - Reporting Security Issues to Citrix


|Date                               |Change                                   |
|14th March 2017                    |Initial publishing                       |

- --------------------------END INCLUDED TEXT--------------------

You have received this e-mail bulletin as a result of your organisation's
registration with AusCERT. The mailing list you are subscribed to is
maintained within your organisation, so if you do not wish to continue
receiving these bulletins you should contact your local IT manager. If
you do not know who that is, please send an email to auscert@auscert.org.au
and we will forward your request to the appropriate person.

NOTE: Third Party Rights
This security bulletin is provided as a service to AusCERT's members.  As
AusCERT did not write the document quoted above, AusCERT has had no control
over its content. The decision to follow or act on information or advice
contained in this security bulletin is the responsibility of each user or
organisation, and should be considered in accordance with your organisation's
site policies and procedures. AusCERT takes no responsibility for consequences
which may arise from following or acting on information or advice contained in
this security bulletin.

NOTE: This is only the original release of the security bulletin.  It may
not be updated when updates to the original are made.  If downloading at
a later date, it is recommended that the bulletin is retrieved directly
from the author's website to ensure that the information is still current.

Contact information for the authors of the original document is included
in the Security Bulletin above.  If you have any questions or need further
information, please contact them directly.

Previous advisories and external security bulletins can be retrieved from:


Australian Computer Emergency Response Team
The University of Queensland
Qld 4072

Internet Email: auscert@auscert.org.au
Facsimile:      (07) 3365 7031
Telephone:      (07) 3365 4417 (International: +61 7 3365 4417)
                AusCERT personnel answer during Queensland business hours
                which are GMT+10:00 (AEST).
                On call after hours for member emergencies only.
Comment: https://auscert.org.au/gpg-key/