The vmware-vga driver (hw/display/vmware_vga.c) in QEMU allows local guest users to write to qemu memory locations and gain privileges via unspecified parameters related to rectangle handling.
The sosendto function in slirp/udp.c in QEMU before 2.1.2 allows local users to cause a denial of service (NULL pointer dereference) by sending a udp packet with a value of 0 in the source port and address, which triggers access of an uninitialized socket.
hw/net/vmxnet3.c in QEMU 2.0.0-rc0, 1.7.1, and earlier allows local guest users to cause a denial of service or possibly execute arbitrary code via vectors related to (1) RX or (2) TX queue numbers or (3) interrupt indices. NOTE: some of these details are obtained from third party information.
Integer overflow in the virtio_net_handle_mac function in hw/net/virtio-net.c in QEMU 2.0 and earlier allows local guest users to execute arbitrary code via a MAC addresses table update request, which triggers a heap-based buffer overflow.