A server-side script is code that runs on the application’s backend, not in the user’s browser. It may process forms, query databases, enforce access rules, generate pages, or call internal services. Because it executes with the server’s privileges, it can reach sensitive data and trusted functions that client-side code cannot.
In cybersecurity, server-side scripts matter because flaws in their handling can lead to serious impact: injection, command execution, data theft, or sandbox escapes. Defenders try to reduce risk by validating input, isolating execution, limiting available APIs, and logging unusual script activity. Attackers often target server-side script paths because they can turn a small input flaw into control of the backend system, especially when the code runs before authentication or outside a strong security boundary.