Host Validation

Validate Host Authority Before Trusting Request Metadata

HTTP applications often need to know which host a client intended to reach. Frameworks expose that value through fields such as Host, request.host, or a parsed request authority. It can look like infrastructure metadata, but at an application boundary it is commonly influenced by the client. That distinction matters when an application uses the value for security-sensitive work. A hostile authority can affect absolute links, redirects, cache entries, tenant selection, origin checks, or routing decisions if the application accepts it without a trust policy.