spice-gtk is a set of GObject and Gtk objects for connecting to Spice servers and a client GUI.
spice-gtk does not properly sanitize the DBUS_SYSTEM_BUS_ADDRESS environment variable.
A local attacker may be able to gain escalated privileges.
There is no known workaround at this time.
All spice-gtk users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=net-misc/spice-gtk-0.14"