The esp_reg_write function in hw/scsi/esp.c in the 53C9X Fast SCSI Controller (FSC) support in QEMU does not properly check command buffer length, which allows local guest OS administrators to cause a denial of service (out-of-bounds write and QEMU process crash) or potentially execute arbitrary code on the QEMU host via unspecified vectors.
https://security.gentoo.org/glsa/201609-01
https://lists.gnu.org/archive/html/qemu-devel/2016-05/msg03273.html
https://lists.debian.org/debian-lts-announce/2018/11/msg00038.html
https://bugzilla.redhat.com/show_bug.cgi?id=1337502
http://www.ubuntu.com/usn/USN-3047-2
http://www.ubuntu.com/usn/USN-3047-1