Deno is a secure runtime for JavaScript and TypeScript that enhances security, simplifies module management, and supports TypeScript out of the box. It uses Promise queues and task batching to manage concurrency more efficiently, preventing potential issues from asynchronous code execution. This approach provides better handling of large numbers of tasks without risking memory overload or complete failure in case of a single task error. By adopting secure coding practices and being mindful of the permissions granted to Deno applications, developers can effectively mitigate the risk of SSRF vulnerabilities.