Yes, you're totally safe then. I've never heard of standard libraries having problems that affect security, certainly not the str* family of functions.
The pain of having worked under these conditions of not using libraries, usually having to work with subpar libraries that were developed internally.
Like oh, hey, we need a database, great, lets roll our own. Or the ancient version of whatever lib shipped with the OS that is full of bugs solved in subsequent versions.
I see that you now use a lot of dependencies, and retract my statement.
Feel free to check out my work. You’ll see the quality bar I set for myself. Almost all of the repos are code that I incorporate into my projects. I just. Plain. Don’t. Trust. most code out there.
I can see the kitchen from the lunch counter, and I’m a damn good cook, myself.
I won’t tell anyone else what to do (unless I’m paying them), but I refuse to add code to my projects that I don’t trust completely (which is, I know, not a guarantee, but it’s a pretty good bet).
I have to rely on the core libraries and development tools I use, but, if I have my druthers, I am picky as hell.
Seriously. Look at my stuff. You’ll see that I put my work where my mouth is.