As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AT FL 260, AIRCRAFT EXPERIENCED A RAPID CLIMB IN CABIN PRESSURE CREW DESCENDED TO FL 120 AND LANDED IN (MKE). PRESSURIZED A/C TO 1.5 DPSI NO MAJOR LEAKS NOTED. INSPECTED ALL DOOR SEALS, AIRCRAFT EXTERIOR AND OUT FLOW VALVE. NO DEFECTS NOTE. A/C IS SAFE FOR PRESSURIZED FLIGHT.