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 block_size and logical_sector_size variables. These are used to derive other fields like 'sectors_per_block' etc. A user able to alter the Qemu disk image could ise this flaw to crash the Qemu instance resulting in DoS.