DOM based cookie bomb

Hi, I would like to report an issue that allows attackers to plant a "cookie bomb" on a victim's browser, so that the victim will be unable to access any Twitter services.

function d(a) {
...
        var b = document.referrer || "none",
            d = "ev_redir_" + encodeURIComponent(a) + "=" + b + "; path=/";
        document.cookie = d;
...
}
...
window.location.hash != "" && d(window.location.hash.substr(1).toLowerCase())