hw/display/bochs-display.c in QEMU 4.0.0 does not ensure a sufficient PCI config space allocation, leading to a buffer overflow involving the PCIe extended config space.
http://lists.opensuse.org/opensuse-security-announce/2020-04/msg00007.html
https://lists.gnu.org/archive/html/qemu-devel/2019-08/msg01959.html