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AUSCERT External Security Bulletin Redistribution
ESB-2021.0681
Citrix Hypervisor Security Update
24 February 2021
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AusCERT Security Bulletin Summary
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Product: Citrix Hypervisor
Publisher: Citrix
Operating System: Virtualisation
Citrix XenServer
Impact/Access: Denial of Service -- Existing Account
Resolution: Patch/Upgrade
CVE Names: CVE-2021-26932 CVE-2021-26931 CVE-2021-26930
Reference: ESB-2021.0586
ESB-2021.0585
ESB-2021.0582
Original Bulletin:
https://support.citrix.com/article/CTX296603
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Citrix Hypervisor Security Update
Reference: CTX296603
Category : Medium
Created : 16 February 2021
Modified : 23 February 2021
Applicable Products
o Citrix Hypervisor
Description of Problem
Several security issues have been identified that, collectively, may allow
privileged code running in a guest VM to cause the host to crash or to become
unresponsive.
These issues have the following CVE identifiers:
CVE ID Description Vulnerability Pre-conditions
Type
An attacker with the ability to CWE-664: Improper Administrator
CVE-2021-26930 execute privileged mode code in Control of a access in
a guest can perform a denial of Resource Through guest
service attack against the host its Lifetime
An attacker with the ability to CWE-664: Improper Administrator
CVE-2021-26931 execute privileged mode code in Control of a access in
a guest can perform a denial of Resource Through guest
service attack against the host its Lifetime
An attacker with the ability to CWE-664: Improper Administrator
CVE-2021-26932 execute privileged mode code in Control of a access in
a guest can perform a denial of Resource Through guest
service attack against the host its Lifetime
All supported versions of Citrix Hypervisor are affected by these issues.
What Customers Should Do
Citrix has released hotfixes to address these 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: CTX294145 -
https://support.citrix.com/article/CTX294145
Citrix Hypervisor 7.1 LTSR: CTX294143 -
https://support.citrix.com/article/CTX294143
Citrix Hypervisor 7.0: CTX294141 -
https://support.citrix.com/article/CTX294141
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.
Changelog
Date Change
2021-02-16 Initial Publication
Disclaimer
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.
- --------------------------END INCLUDED TEXT--------------------
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