The v9fs_iov_vunmarshal function in fsdev/9p-iov-marshal.c in QEMU (aka Quick Emulator) allows local guest OS administrators to cause a denial of service (NULL pointer dereference and QEMU process crash) by sending an empty string parameter to a 9P operation.
lists.opensuse.org/opensuse-updates/2016-12/msg00140.html
www.openwall.com/lists/oss-security/2016/10/10/14
www.openwall.com/lists/oss-security/2016/10/10/8
www.securityfocus.com/bid/93474
lists.debian.org/debian-lts-announce/2018/11/msg00038.html
lists.gnu.org/archive/html/qemu-devel/2016-09/msg07143.html
security.gentoo.org/glsa/201611-11