CVE-2016-9637: Citrix Xenserver

High severity, CVSS 7.5. EPSS: 0.4% chance of exploitation in the next 30 days.

The (1) ioport_read and (2) ioport_write functions in Xen, when qemu is used as a device model within Xen, might allow local x86 HVM guest OS administrators to gain qemu process privileges via vectors involving an out-of-range ioport access.

Affected products

• Citrix Xenserver: version 6.0.2 only; version 6.2.0 only; version 6.5 only; version 7.0 only

Published 2017-02-17. Last modified 2026-06-17.