All the memory safety vulnerabilities, which are the majority of bugs in most C/C++ projects?

> Give an example of UB code that you have committed in real life

    struct foo {
        ...
        atomic_int v;
        ...
    };
    
    struct foo x;
    memset(&x, 0, sizeof(x));

I don't think it's UB if you init the struct before using it atomically from multiple threads.