It is possible to set the size of the allocation heap to a total size (such as zero) that is too small to handle any allocations. The C library's dynamic memory allocation routines (e.g. malloc) did not gracefully handle allocations in this case. These functions might crash, or might scribble on unrelated program memory, or might return successfully with a bogus pointer, in which case the caller would likely proceed to write through the bogus pointer and scribble on arbitrary memory.