https://seclists.org/oss-sec/2026/q4/142: Xen Security Advisory 514 v2 (CVE-2026-79607) - XenstoGuests can crash xenstod during Live Update
Published Oct 13, 2026
·Updated
Affected Software
1 affected component
XEN Xen=4.22
Frequently Asked Questions
1
Which Xen deployments are affected?
Only Xen 4.22 systems using the C Xenstore implementation are vulnerable, whether it runs as a daemon or as a stubdom. Xen 4.21 and older are not vulnerable, and oxenstored is not affected.
2
What must an attacker be able to do?
An unprivileged guest can trigger the issue during a Xenstore live update. The flaw involves Xenstore watches configured with a specified watch depth.
3
What is the operational impact?
The Xenstore service can crash or its data can become corrupted during the live update. This can prevent further domain administration actions on the host.
4
What can be done if an update cannot be applied immediately?
Avoid performing Xenstore live updates, which avoids the vulnerable code path. Switching from the C Xenstore implementation to oxenstored also avoids the vulnerability.