For generalist developers who have to get things done: learn at least a little about the major classes of security vulnerabilities that impact your development environment, and select libraries designed to mitigate them.

For students: learn a lot about the most important classes of security vulnerabilities, of which memory corruption is one important example but just one, and then take the time to learn how to exploit at least simple variants of all of them in a realistic setting, to cultivate the mindset needed to think critically about software security.

Don't write anything in C. Sure. But really almost nobody does that anymore anyways.