Citrix XenServer Multiple Security Updates

A number of security vulnerabilities have been identified in Citrix XenServer that may allow a malicious administrator of a guest VM to compromise the host.

These vulnerabilities affect all currently supported versions of Citrix XenServer up to and including Citrix XenServer 7.2.

The following vulnerabilities have been addressed:

• CVE-2017-15595: Unlimited recursion in linear pagetable de-typing
• CVE-2017-15588: Stale TLB entry due to page type release race
• CVE-2017-15593: page type reference leak on x86
• CVE-2017-15592: x86: Incorrect handling of self-linear shadow mappings with translated guests
• CVE-2017-15594: x86: Incorrect handling of IST settings during CPU hotplug
• CVE-2017-15590: multiple MSI mapping issues on x86
• CVE-2017-15589: hypervisor stack leak in x86 I/O intercept code

For customers that do not have PV-based guests, are not using PCI passthrough and are using hardware with HAP support, the risk is reduced to a disclosure of a small part of the hypervisor stack.

Hotfixes have been released to address these issues. Citrix strongly recommends that affected customers install these hotfixes as soon as possible. The hotfixes can be downloaded from the following locations:

Citrix XenServer 7.2: CTX228722 – https://support.citrix.com/article/CTX228722 

Citrix XenServer 7.1 LTSR CU1: CTX228721 – https://support.citrix.com/article/CTX228721 

Citrix XenServer 7.1 LTSR: CTX228720 – https://support.citrix.com/article/CTX228720 

Citrix XenServer 7.0: CTX228719 – https://support.citrix.com/article/CTX228719 

Citrix XenServer 6.5 SP1: CTX228718 – https://support.citrix.com/article/CTX228718 

Citrix XenServer 6.2 SP1: CTX228717 – https://support.citrix.com/article/CTX228717 

Citrix XenServer 6.0.2 Common Criteria: CTX228716 – https://support.citrix.com/article/CTX228716