Rails, short for Ruby on Rails, is a server-side web application framework for building websites and APIs in Ruby. It gives developers a standard structure for routing requests, handling forms, managing sessions, processing files, and connecting to databases. That structure speeds up development, but it also means a flaw in one framework feature can affect many applications that rely on it.
In cyber security, Rails matters because attackers often target the framework layer, not just a single app. If a vulnerability affects file upload handling, request parsing, or object deserialization, it can lead to data exposure, secret leakage, or remote code execution. Defenders should know which Rails version is deployed, whether vulnerable components are enabled, and whether the app stores sensitive credentials near the web process. When a Rails issue is actively exploited, patching, log review, and secret rotation become urgent.