The rtl8139_cplus_transmit function in hw/net/rtl8139.c in QEMU (aka Quick Emulator) allows local guest OS administrators to cause a denial of service (infinite loop and CPU consumption) by leveraging failure to limit the ring descriptor count.
https://security.gentoo.org/glsa/201611-11
https://lists.gnu.org/archive/html/qemu-devel/2016-10/msg05495.html
https://lists.debian.org/debian-lts-announce/2018/11/msg00038.html
https://access.redhat.com/errata/RHSA-2017:2408
https://access.redhat.com/errata/RHSA-2017:2392
http://www.securityfocus.com/bid/93844
http://www.openwall.com/lists/oss-security/2016/10/24/5
http://www.openwall.com/lists/oss-security/2016/10/24/2
http://lists.opensuse.org/opensuse-updates/2016-12/msg00140.html