Nibodhika , 3 months ago

Not really, the issue is that C/C++ is not memory safe, i.e. it allows you to access memory that has already been freed. Consider the following C++ code:

<span style="font-weight:bold;color:#a71d5d;">int* </span><span style="font-weight:bold;color:#795da3;">wrong</span><span style="color:#323232;">() {
</span><span style="color:#323232;">  </span><span style="font-weight:bold;color:#a71d5d;">int</span><span style="color:#323232;"> data  </span><span style="font-weight:bold;color:#a71d5d;">= </span><span style="color:#0086b3;">10</span><span style="color:#323232;">;
</span><span style="color:#323232;">  </span><span style="font-weight:bold;color:#a71d5d;">return &</span><span style="color:#323232;">data;
</span><span style="color:#323232;">}
</span>

If you try to use it it looks correct:

<span style="font-weight:bold;color:#a71d5d;">int*</span><span style="color:#323232;"> ptr </span><span style="font-weight:bold;color:#a71d5d;">= </span><span style="color:#323232;">wrong();
</span><span style="color:#323232;">std::cout </span><span style="font-weight:bold;color:#a71d5d;"><< *</span><span style="color:#323232;">ptr </span><span style="font-weight:bold;color:#a71d5d;"><<</span><span style="color:#323232;"> std::endl;
</span>

That will print 10, but the memory where data was defined has been freed, and is no longer in control of the program. Meaning that if something else allocated that memory they can control what my program does.

Consider that on that example above later in the program we do:

<span style="color:#323232;">user.access_level </span><span style="font-weight:bold;color:#a71d5d;">= *</span><span style="color:#323232;">ptr;
</span>

If someone manages to get control of that memory between when we freed it and we used it they can make the access_level of the user be whatever they want.

This is a problem with C/C++ allowing you to access memory that has been freed, which is why C/C++ programmers need to be extra careful.