Off-by-one error in the cmdsmart function in the smart self test in hw/ide/core.c in QEMU before 2.0 allows local users to have unspecified impact via a SMART EXECUTE OFFLINE command that triggers a buffer underflow and memory corruption.
Buffer overflow in the usbhosthandlecontrol function in the USB passthrough handling implementation in usb-linux.c in QEMU before 0.11.1 allows guest OS users to cause a denial of service (guest OS crash or hang) or possibly execute arbitrary code on the host OS via a crafted USB packet.
A buffer overflow flaw was found in the way qemu processed MAC addresses table update requests from the guest.
A privileged guest user could use this flaw to corrupt qemu process memory on the host, which could potentially result in arbitrary code execution on the host with the privileges of the qemu process.
Acknowledgements:
This issue was discovered by Michael S. Tsirkin of Red Hat.