Server-side rendering (SSR) is the process of generating a web page’s HTML on a server before sending it to a browser. Unlike client-side rendering, where the browser builds much of the page using JavaScript, SSR performs that work on the backend. It can improve initial page display and search-engine visibility, but also makes rendering code and input parsing part of the server’s attack surface.
In security, a flaw in an SSR parser or rendering path can affect service availability or expose server-side data. For example, malformed input that triggers an infinite loop can consume CPU and stall requests handled by the same process. Defenders should keep SSR frameworks and dependencies patched, review whether untrusted content reaches server-side parsing, and monitor CPU use and request latency for unexpected changes.