QEMU 0.9.0 allows local users of a Windows XP SP2 guest operating system to overwrite the TranslationBlock (code_gen_buffer) buffer, and probably have unspecified other impacts related to an "overflow," via certain Windows executable programs, as demonstrated by qemu-dos.com.
Improper Restriction of Operations within the Bounds of a Memory Buffer The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary.