What is the implication of this trend for security?

My casual impression is that this trend ("Rewriting built-in modules in C")
can introduce a number of nasty memory-related bugs, especially if these
modules involve tricky data structures.

Yes, C is definitely faster and will improve benchmark results. But a whole
class of issues (overflow, memory corruption etc.) can be avoided if we stick
to Python.

So: will the trend make CPython more insecure? Or is this not the case?