The xhci_kick_epctx function in hw/usb/hcd-xhci.c in QEMU (aka Quick Emulator) allows local guest OS privileged users to cause a denial of service (infinite loop and QEMU process crash) via vectors related to control transfer descriptor sequence.
https://security.gentoo.org/glsa/201704-01
https://lists.gnu.org/archive/html/qemu-devel/2017-02/msg01101.html
https://lists.debian.org/debian-lts-announce/2018/09/msg00007.html
https://bugzilla.redhat.com/show_bug.cgi?id=1421626
https://access.redhat.com/errata/RHSA-2017:2408
https://access.redhat.com/errata/RHSA-2017:2392