Edge Computing with Cloudflare Workers & Deno · Lesson

Input Sanitization & Injection Prevention

Defend edge applications against XSS, SQL injection, and related attacks by sanitizing input and encoding output correctly.

Why Sanitization Matters

Even at the edge, untrusted input is the root of most attacks. Sanitization and proper output encoding stop:

Validation checks shape, sanitization makes input safe to use.

XSS happens when attacker-controlled data is rendered as HTML and executes as script.

If a Worker echoes user input into a page without encoding, an attacker can inject scripts.

// Dangerous: user input goes straight into HTML
const html = '<div>' + userInput + '</div>';