A breakdown comparing the language that caused the errors would be helpful. I expect that codebases in C or C++03 or even (idk) C++14 have much higher rate of memory corruption derived vulnerabilities, than those written in C++20.
I agree in the abstract, but people like to argue about if a codebase is truly "Modern C++" or not, even when they use newer versions of C++, due to it largely being about patterns and the amount of them. So you'll have people nitpick this to death.
Except even in C++20 there will the clever dudes writting C strings/arrays, doing strcpy, memset, memcpy,... botching all best efforts for safety.
Just go around open source projects from well known ISO C++ members.