gnome-boxes fails to start a vm with qemu 2.12

gnome-boxes fails to start any os for me, with qemu 2.12 (in this case F28), but have same results with win10, ubuntu 18.04, ...

Boxes-WARNING **: 13:32:21.781: machine.vala:620: Failed to start Fedora: Unable to start domain: internal error: qemu unexpectedly closed the monitor: 2018-05-04T11:32:21.741877Z qemu-system-x86_64: -device ccid-card-passthru,chardev=charsmartcard0,id=smartcard0,bus=ccid0.0: ccid-card-passthru: initing chardev

Additional info:

• qemu 2.12.0-1
• libvirt 4.2.0-1
• gnome-boxes 3.28.2-1

Steps to reproduce:

start gnome-boxes, try to add an iso by choosing its file, start it, the vm quits immediatly