QEMU before 2.0.0 block drivers for CLOOP, QCOW2 version 2 and various other image formats are vulnerable to potential memory corruptions, integer/buffer overflows or crash caused by missing input validations which could allow a remote user to execute arbitrary code on the host with the privileges of the QEMU process.

Qemu before 1.6.2 block diver for the various disk image formats used by Bochs and for the QCOW version 2 format, are vulnerable to a possible crash caused by signed data types or a logic error while creating QCOW2 snapshots, which leads to incorrectly calling updaterefcount() routine.

Qemu before 2.0 block driver for Hyper-V VHDX Images is vulnerable to infinite loops and other potential issues when calculating BAT entries, due to missing bounds checks for blocksize and logicalsectorsize variables. These are used to derive other fields like 'sectorsperblock' etc. A user able to alter the Qemu disk image could ise this flaw to crash the Qemu instance resulting in DoS.