Next.js is a React framework that can provide building blocks to create web applications. A Server-Side Request Forgery (SSRF) vulnerability was identified in Next.js Server Actions. If the `Host` header modified, and below conditions are also met, an attacker may be able make requests appear originating from application server itself. The required 1) running self-hosted manner; 2) makes use of Actions; 3) Action performs redirect relative path which starts with `/`. This fixed `14.1.1`.