CDN/WAF refers to edge security layers that combine content delivery with request filtering. A CDN moves traffic closer to users and can mask or protect the origin service, while a WAF inspects HTTP requests for suspicious patterns, such as injection payloads, exploit probes, abusive bots, and excessive request rates. In practice, these controls sit in front of web apps and APIs so malicious traffic can be blocked before it reaches the application tier.
In cyber security, CDN/WAF protection matters because many attacks start at the perimeter: scanning, credential stuffing, scraping, and attempts to exploit common web flaws. Edge controls can absorb spikes, enforce rate limits, and drop known-bad traffic early, reducing load on back-end systems. They are useful for runtime defense, but they are not a full substitute for secure code, strong authentication, and API authorization, since they mainly see traffic at the edge and may not understand every business rule inside the application.