The vga display update in mis-calculated the region for the dirty bitmap snapshot in case split screen mode is used causing a denial of service (assertion failure) in the cpu_physical_memory_snapshot_get_dirty function.
http://lists.opensuse.org/opensuse-security-announce/2019-03/msg00042.html
https://access.redhat.com/errata/RHSA-2018:1104
https://access.redhat.com/errata/RHSA-2018:1113
https://lists.gnu.org/archive/html/qemu-devel/2017-08/msg04685.html