Since Nim transpiles itself down to C code, and then compiles it to assembly, and machine code. Then, how does Nim avoid the occasional security issues, buffer

Since Nim transpiles itself down to C code, and then compiles it to assembly, and machine code. Then, how does Nim avoid the occasional security issues, buffer overflows, and other undefined behavior problems that always arises from C written programs? Is this not a concern? Or is Nim fully vetted, that it doesn’t use defective C libraries?