The virDomainGetXMLDesc API in Libvirt before 1.2.11 allows remote read-only users to obtain the VNC password by using the VIRDOMAINXMLMIGRATABLE flag, which triggers the use of the VIRDOMAINXMLSECURE flag.
{ "availability": "No subscription required", "ubuntu_priority": "medium", "binaries": [ { "libvirt-dev": "1.2.2-0ubuntu13.1.7", "libvirt-doc": "1.2.2-0ubuntu13.1.7", "libvirt0-dbg": "1.2.2-0ubuntu13.1.7", "libvirt0": "1.2.2-0ubuntu13.1.7", "libvirt-bin": "1.2.2-0ubuntu13.1.7" } ] }