rcube_webmail.prototype.managesieve_setget = function()
{
  var id = this.filtersets_list.get_single_selection(),
    script = this.env.filtersets[id];

  location.href = this.env.comm_path+'&_action=plugin.managesieve-action&_act=setget&_set='+urlencode(script);
};
The web application does not, or can not, sufficiently verify whether a well-formed, valid, consistent request was intentionally provided by the user who submitted the request.