As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
EWR - FLT 3113 THE CREW REPORTED THE CREW OXYGEN SYSTEM WAS LEAKING DOWN IN FLIGHT. THE AIRCRAFT DIVERTED INTO CLE AND LANDED WITHOUT INCIDENT. MAINTENANCE INSPECTED AND FOUND A LOOSE LINE AT THE FIRST OFFICER'S OXYGEN MASK STOWAGE BOX. TIGHTENED LINE AND OPERATIONAL CHECKS WERE GOOD.