Where are pointers in C++ stored, on the stack or in the heap?

Your understanding may be correct, but the statements are wrong:

A pointer to object m has been allocated on the stack.

m is the pointer. It is on the stack. Perhaps you meant pointer to a Member object.

The object m itself (the data that it carries, as well as access to its methods) has been allocated on the heap.

Correct would be to say the object pointed by m is created on the heap

In general, any function/method local object and function parameters are created on the stack. Since m is a function local object, it is on the stack, but the object pointed to by m is on the heap.