qemu:xenial is vulnerable to Memory leak. Due to a flaw in hw/audio/ac97.c in QEMU (aka Quick Emulator), it allows local guest OS privileged users to cause a denial of service (host memory consumption and QEMU process crash) via a large number of device unplug operations.
git.qemu-project.org/?p=qemu.git%3Ba=commit%3Bh=12351a91da97b414eec8cdb09f1d9f41e535a401
git.qemu-project.org/?p=qemu.git;a=commit;h=12351a91da97b414eec8cdb09f1d9f41e535a401
www.openwall.com/lists/oss-security/2017/01/17/19
www.openwall.com/lists/oss-security/2017/01/18/7
www.securityfocus.com/bid/95671
lists.debian.org/debian-lts-announce/2018/09/msg00007.html
security.gentoo.org/glsa/201702-28