A templating engine is software that combines template text with variables, data, or expressions to produce a rendered page, email, report, or other output. Instead of hardcoding every value, developers define placeholders and let the engine fill them in at runtime.
In cyber security, templating engines matter because they sit at the boundary between data and executable logic. If untrusted input reaches a template without proper escaping or isolation, an attacker may inject markup, script, or template expressions, leading to cross-site scripting, server-side template injection, or even code execution in some systems. Defenders reduce this risk by treating user input as data only, using context-aware escaping, disabling dangerous template features, and limiting who can edit templates. Secure use of templating engines is essential in web apps, portals, and workflow platforms where dynamic content is common.