FreeScout is a free, self-hosted help desk and shared mailbox. Versions of FreeScout prior to 1.8.139 contain a Prototype Pollution vulnerability in the `/public/js/main.js` source file. The Prototype Pollution arises because the `getQueryParam` Function recursively merges an object containing user-controllable properties into an existing object (For URL Query Parameters Parsing), without first sanitizing the keys. This can allow an attacker to inject a property with a key `__proto__`, along with arbitrarily nested properties. The merge operation assigns the nested properties to the `params` object's prototype instead of the target object itself. As a result, the attacker can pollute the prototype with properties containing harmful values, which are then inherited by user-defined objects a