CVE-2023-30456

A flaw was found in the KVM's Intel nested virtualization feature (nVMX). The effective values of the guest CR0 and CR4 registers could differ from those included in the VMCS12. In rare circumstances (i.e., kvm_intel module loaded with parameters nested=1 and ept=0) this could allow a malicious guest to crash the host system, causing a denial of service.

Red Hat currently provides the nested virtualization feature as a Technology Preview. Nested virtualization is therefore unsupported for production use. For more information please refer to https://access.redhat.com/solutions/21101 and https://access.redhat.com/support/offerings/techpreview.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

This vulnerability can be mitigated by disabling the nested virtualization feature:

# modprobe -r kvm_intel
# modprobe kvm_intel nested=0