The esp_do_dma function in hw/scsi/esp.c in QEMU (aka Quick Emulator), when built with ESP/NCR53C9x controller emulation support, allows local guest OS administrators to cause a denial of service (out-of-bounds write and QEMU process crash) or execute arbitrary code on the QEMU host via vectors involving DMA read into ESP command buffer.
https://lists.debian.org/debian-lts-announce/2018/11/msg00038.html
http://www.openwall.com/lists/oss-security/2016/07/25/14
http://www.openwall.com/lists/oss-security/2016/07/26/7