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.
{
"binaries": [
{
"binary_version": "1.2.2-0ubuntu13.1.7",
"binary_name": "libvirt-bin"
},
{
"binary_version": "1.2.2-0ubuntu13.1.7",
"binary_name": "libvirt-dev"
},
{
"binary_version": "1.2.2-0ubuntu13.1.7",
"binary_name": "libvirt0"
}
],
"availability": "No subscription required"
}