PT-2026-111667

CVE-2026-79611

Published

2026-10-13

Updated

2026-11-09

Description by

CVSS 3.1

5.5

Medium

MetricsAV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Name of the Vulnerable Software and Affected Versions XenServer versions 8.4 through 9

Description A logic error exists in the handling of XSA-308 where VMX VMEntry checks fail when a specific state combination occurs: #DB is intercepted, Single Stepping is active, and blocked by STI/MovSS is active. This failure is fatal to the guest. A similar issue occurs when branch tracing is enabled, also resulting in a fatal VMEntry failure for the guest.

Recommendations Update XenServer versions 8.4 through 9 to the latest version.

Exploitability

Fix

Impacts

Researchers

Claude Opus

Vendors

Affected products

Weakness enumeration

CWE-843: Access of Resource Using Incompatible Type (\'Type Confusion\')

Related identifiers

CVE-2026-79611