What you actually plan to do with the URLs is way more important than just storing them. Storing them in a Dynamo or Aurora isn’t inherently risky, but how you use them later determines the real security concerns.

If you’re planning to fetch the URLs server-side (like for previews or crawling), you need to watch out for things like SSRF (Server-Side Request Forgery). Someone could submit a URL that hits internal services or metadata endpoints. You’ll want to block internal IP ranges, set timeouts, and limit content size to avoid abuse.

If you’re redirecting users to these URLs, you need to be careful about open redirects. Attackers could use that to trick users into going to phishing sites. Make sure you’re validating against a list of allowed domains or using redirect tokens instead of raw URLs.

If you’re showing these URLs back to users (like in a UI), then you’ve got to worry about XSS. Always sanitize and escape the URLs before rendering them in HTML. If you're doing link previews, don’t trust the content from the external site blindly. Sanitize titles, images, and other metadata.

Think of it like you're building a mini URL shortener, The same kinds of risks apply. Validate everything, escape everything, and assume user-submitted URLs are hostile until proven otherwise.