Turbopack is a Next.js build tool and bundler. It takes application code, resolves imports, and produces the assets and server output a framework uses at runtime. Like other bundlers, it shapes how routes, middleware, and modules are organized before the app is deployed.
In security terms, Turbopack matters because build and routing choices can change the attack surface. A flaw may not be in Turbopack itself, but in a deployment pattern that depends on its output, such as authentication checks performed too close to framework routing logic. Attackers look for gaps between build-time assumptions and runtime behavior, while defenders use the same knowledge to review configurations, verify authorization in server-side code, and test whether a specific build setup exposes request handling weaknesses.