As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLT 1258 IAD-BOS, WHILE AIRCRAFT WAS SLOWING AND BEING VECTORED ON APPROACH, THE FLIGHT ATTENDANTS CALLED TO SAY A BURNING SMELL LIKE BURNING RUBBER WAS AROUND ROW 23. THERE WAS NO SMOKE OR FIRE JUST SMELL. IT DISSIPATED AFTER ABOUT 3-4 MINUTES. PERFORMED INSPECTION AND FOUND SMELL TO BE COMING FROM XEB AT ROW 23AB PER AMM 21-20-00-810-801-A. REMOVED AND REPLACED XEB AT SEAT 23AB. INSPECTED ALL XEB'S AND XEB CONNECTORS THROUGHOUT THE CABIN NO DEFECTS OR SMOKE SMELL FOUND.