Integer overflow in the load_multiboot function in hw/i386/multiboot.c in QEMU (aka Quick Emulator) allows local guest OS users to execute arbitrary code on the host via crafted multiboot header address values, which trigger an out-of-bounds write.
The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.