The VMX process in VMware ESXi 4.1 and ESX 4.1 does not properly handle RPC commands, which allows guest OS users to cause a denial of service (memory overwrite and process crash) or possibly execute arbitrary code on the host OS via vectors involving function pointers.
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.