## Description of Problem Several security issues have been identified that, collectively, may allow privileged code running in a guest VM to compromise the host or cause a denial of service. These vulnerabilities have the following identifiers: CVE ID| Description| Vulnerability Type| Pre-conditions ---|---|---|--- CVE-2020-29479| An attacker with the ability to execute privileged mode code in a guest can compromise the host| CWE-707: Improper Neutralization| Administrator access in guest CVE-2020-29480| An attacker with the ability to execute privileged mode code in a guest can read non-sensitive metadata about another guest| CWE-284: Improper Access Control| Administrator access in guest CVE-2020-29481| An attacker with the ability to execute privileged mode code in a guest can read data previously shared, using the Xenstore API, between two other guests| CWE-664: Improper Control of a Resource Through its Lifetime| Administrator access in guest CVE-2020-29482| An attacker with the ability to execute privileged mode code in a guest can perform a denial of service attack against the host| CWE-664: Improper Control of a Resource Through its Lifetime| Administrator access in guest CVE-2020-29485| An attacker with the ability to execute privileged mode code in a guest can perform a denial of service attack against the host| CWE-664: Improper Control of a Resource Through its Lifetime| Administrator access in guest CVE-2020-29486| An attacker with the ability to execute privileged mode code in a guest can perform a denial of service attack against the host or a selected other VM| CWE-664: Improper Control of a Resource Through its Lifetime| Administrator access in guest CVE-2020-29487| An attacker with the ability to execute privileged mode code in a guest can perform a denial of service attack against the host| CWE-664: Improper Control of a Resource Through its Lifetime| Administrator access in guest CVE-2020-29568| An attacker with the ability to execute privileged mode code in a guest can perform a denial of service attack against the host| CWE-664: Improper Control of a Resource Through its Lifetime| Administrator access in guest CVE-2020-29569| An attacker with the ability to execute privileged mode code in a guest can perform a denial of service attack against the host| CWE-664: Improper Control of a Resource Through its Lifetime| Administrator access in guest CVE-2020-29570| An attacker with the ability to execute privileged mode code in a guest can perform a denial of service attack against the host| CWE-664: Improper Control of a Resource Through its Lifetime| Administrator access in guest These issues affect all currently supported versions of Citrix Hypervisor up to and including Citrix Hypervisor 8.2 LTSR. ## What Customers Should Do Citrix has released hotfixes to address these issues. Citrix recommends that affected customers install these hotfixes as soon as practicable. The hotfixes can be downloaded from the following locations: Citrix Hypervisor 8.2 LTSR: CTX286796 – and CTX286800 – and CTX286804 – Citrix Hypervisor 8.1: CTX286795 – and CTX286799 – and CTX286803 – Citrix XenServer 7.1 LTSR CU2: CTX286794 – and CTX286798 – and CTX286802 – Citrix XenServer 7.0: CTX286793 – and CTX286797 – and CTX286801 – ## 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 . ## 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 . ## Reporting Security Vulnerabilities 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: – ## Disclaimer 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 ---|--- 2020-12-15| Initial Publication ##