A flaw was found in Next.js, a React framework for building web applications. A remote attacker can send specially crafted requests to Next.js applications that utilize the App Router with Server Actions. This can lead to excessive CPU usage, causing the application to become unresponsive and preventing it from processing further requests, resulting in a Denial of Service (DoS).

Next.js is a React framework for building full-stack web applications. In versions 13.0.0 through 15.5.20 and 16.0.0 through 16.2.10, crafted requests targeting Next.js applications using App Router with at least one Server Action can lead to excessive CPU usage blocking processing of further requests in the same process. This issue has been fixed in versions 15.5.21 and 16.2.11.

Next.js: Denial of Service in App Router using Server Actions