Unauthenticated Denial of Service in nltk.app.wordnet_app

A vulnerability in nltk.app.wordnet_app up to version 3.9.3 allows unauthenticated remote shutdown of the local WordNet Browser HTTP server when started in its default mode. The server listens on all interfaces and processes a specific unauthenticated GET request (/SHUTDOWN%20THE%20SERVER) to terminate the process immediately via os._exit(0). This results in a denial of service, impacting service availability. The issue arises due to insufficient authentication and protection mechanisms for critical server functions.