Access global memory from different CPU threads

I have read that there is no memory protection on gpu:
"There is no memory protection for allocations on the GPU between
different MPI processes (one MPI process can access GPU memory
allocated by another process) "
Is it still true? Or it is limited e.g to threads created by one application. I would like to pass pointer to other application (other .exe) on the same machine and want to be able to read data that are on gpu, but in fact allocated by other thread. I know that it is not a good practice but I would like to do so.
Thanks in advance