Directory traversal vulnerability in hw/9pfs/9p.c in QEMU (aka Quick Emulator) allows local guest OS administrators to access host files outside the export path via a .. (dot dot) in an unspecified string.
https://security.gentoo.org/glsa/201609-01
https://lists.gnu.org/archive/html/qemu-devel/2016-08/msg04231.html
https://lists.gnu.org/archive/html/qemu-devel/2016-08/msg03917.html
https://lists.debian.org/debian-lts-announce/2018/11/msg00038.html
http://www.securityfocus.com/bid/92680