Remotely hosted code is program logic that an application fetches from an external server at runtime instead of shipping it inside the reviewed package. In browser extensions, this can mean scripts, rules, or functions loaded after installation, which makes the extension’s behavior harder to predict from the store listing or source bundle alone.
It matters in cybersecurity because it weakens the trust boundary between approved code and code that can change later. Attackers may abuse this pattern to deliver malicious features after review, hide capabilities behind conditional loading, or swap benign behavior for harmful behavior. Defenders often block or restrict remotely hosted code, require all executable code to be packaged locally, and inspect network requests and extension permissions to reduce supply-chain risk.