Quick Emulator (Qemu) built with the 'chardev' backend support is vulnerable to a use after free issue. It could occur while hotplug and unplugging the device in the guest. A guest user/process could use this flaw to crash a Qemu process on the host resulting in DoS.
Gentoo Linux Security Advisory 201701-49 - Multiple vulnerabilities have been found in QEMU, the worst of which could cause a Denial of Service condition. Versions less than 2.8.0 are affected.