CVE-2016-9386: Citrix Xenserver

High severity, CVSS 7.8. EPSS: 0.4% chance of exploitation in the next 30 days.

The x86 emulator in Xen does not properly treat x86 NULL segments as unusable when accessing memory, which might allow local HVM guest users to gain privileges via vectors involving "unexpected" base/limit values.

Affected products

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

Published 2017-01-23. Last modified 2026-06-17.