FreeScout vulnerable to prototype pollution in getQueryParam

FreeScout is a free help desk and shared inbox built with PHP's Laravel framework. A Prototype Pollution condition in the getQueryParam function /public/js/main.js and was addressed in version 1.8.139 by blocking URL query keys matching the pattern __proto__. However, this mitigation is incomplete: it only filters top-level __proto__ keys and fails to sanitize nested forms such as b[__proto__][polluted]=PWNED. As a result, an attacker-controlled URL query string can still write into Object.prototype on any page that loads main.js. Version 1.8.223 contains a updated fix.