As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CRUISE FLIGHT, THE FLIGHT ATTENDANTS IN BACK OF ACFT NOTICED AN ODOR OF DIRTY SOCKS, BURNING FUMES. AFTER TURNING OFF THE NR 2 PACK, THE ODOR DISSIPATED. PERFORMED IDENTIFICATION OF CAUSE OF CABIN ODOR IAW TSM 05-50-00-810-831-A. FOUND GREEN HYDRAULICS OVERSERVICED AND ECO BOTTLE FULL. ODOR CAUSED BY APU INLET INGESTING HYDRAULICS. CLEANED AND EMPTIED THE BOTTLE AND AREA. RAN THE NR 1 & 2 PACKS WITH APU FOR 20 MINUTES. NO ODORS DETECTED. AIRCRAFT RETURNED TO SERVICE.