CVE-2019-10167

The virConnectGetDomainCapabilities() libvirt API accepts an “emulatorbin” argument to specify the program providing emulation for a domain. Since v1.2.19, libvirt will execute that program to probe the domain’s capabilities. Read-only clients could specify an arbitrary path for this argument, causing libvirtd to execute a crafted executable with its own privileges.

Mitigation

The Unix permissions of libvirt's read-only socket can be made more restrictive than the default (0777) by editing /etc/libvirt/libvirtd.conf. The settings unix_sock_group = libvirt and unix_sock_ro_perms = 0770 will restrict access to only members of libvirt, who already have management access to virtual machines.