The get_cmd function in hw/scsi/esp.c in the 53C9X Fast SCSI Controller (FSC) support in QEMU does not properly check DMA length, which allows local guest OS administrators to cause a denial of service (out-of-bounds write and QEMU process crash) via unspecified vectors, involving an SCSI command.
https://security.gentoo.org/glsa/201609-01
https://lists.gnu.org/archive/html/qemu-devel/2016-05/msg03274.html
https://lists.debian.org/debian-lts-announce/2018/11/msg00038.html
https://bugzilla.redhat.com/show_bug.cgi?id=1337505
http://www.ubuntu.com/usn/USN-3047-2
http://www.ubuntu.com/usn/USN-3047-1