TL;DR
Ask any AI editor for a "fetch this URL" feature and it hands the user's raw input straight to your HTTP client. That is SSRF (CWE-918).
The danger is not the public internet. It is your cloud metadata endpoint and internal services that trust anything from your own server.
Block private IP ranges, resolve DNS before you connect, and turn off redirects. Five lines.
I was reviewing a side project last week. It had a neat little feature: paste a link, get a preview card with the title and image. Classic. I asked what generated the backend and the answer was Cursor, one prompt, "add an endpoint that fetches a URL and returns its metadata."
