https://seclists.org/oss-sec/2026/q4/146: Xen Security Advisory 518 v2 (CVE-2026-79611) - VMX: VMentry failuwith branch tracing and blocked states
Published Oct 13, 2026
·Updated
Affected Software
1 affected component
Xen Project Xen
Frequently Asked Questions
1
Which deployments are exposed?
All Xen versions are affected when running HVM or PVH guests on systems with VMX hardware virtualization extensions from Intel, VIA, or Zhaoxin. Arm, AMD, Hygon, and PV guest configurations are unaffected.
2
What access does an attacker need, and what is the impact?
The issue may be triggered by userspace code running inside an HVM or PVH guest. Successful exploitation can crash that guest, causing a guest denial of service.
3
What mitigation is available if an update cannot be applied immediately?
Running only PV guests mitigates the issue, because PV guests cannot leverage the vulnerability.