overzealous russian

• перестара́вшийся

  overzealous, having overdone it, overexerted

• переусе́рдствовавший

  overzealous, overdone, having overexerted oneself, who overdid it

• дорва́вшийся

  having gained access, having seized (an opportunity/power), having broken through, newly empowered (often with a connotation of overzealousness or lack of restraint)