QEMU (Quick Emulator) is a set of emulated processor software from Fabrice Bellard, a French personal developer. QEMU has a denial of service vulnerability, which stems from a deadlock problem in its AHCI controller during a software reset (ahci_reset_port) while processing host-to-device registration FIS (Frame Information Structure) messages from a client, allowing a privileged user in the client to hang the QEMU process on the host, which could be exploited by an attacker to cause a denial of service. exploit this vulnerability to cause a denial of service.