The process_tx_desc function in hw/net/e1000.c in QEMU before 2.4.0.1 does not properly process transmit descriptor data when sending a network packet, which allows attackers to cause a denial of service (infinite loop and guest crash) via unspecified vectors.
The Bluetooth subsystem in QEMU mishandles negative values for length variables, leading to memory corruption.
The PyGrub boot loader in Xen unstable before changeset 25589:60f09d1ab1fe, 4.2.x, and 4.1.x allows local para-virtualized guest users to cause a denial of service (memory consumption) via a large (1) bzip2 or (2) lzma compressed kernel image.
QEMU 4.1.0 has a memory leak in zrle_compress_data in ui/vnc-enc-zrle.c during a VNC disconnect operation because libz is misused, resulting in a situation where memory allocated in deflateInit2 is not freed in deflateEnd.