MD-11 Captain reported a HAZMAT box in the cargo compartment had leaked liquid during cruise. The flight diverted to a suitable airport due to fumes emanating from the cargo compartment.

Narrative

Enroute from ZZZ1 to ZZZ2; approximately 2 hours into flight; FO (First Officer) observed faint odor. Approaching abeam ZZZ; got slightly stronger. FO continued to fly. I went aft to courier compartment to investigate. Odor was stronger there. I reinforced seal of smoke curtain Velcro and returned to cockpit. FO smartly donned O2 while I was out of the seat. Odor was not overwhelming but out of an abundance of caution; diverted to ZZZ. Notified Dispatch and ZZZ Ramp. Got NOTAMs; ATIS; and built and briefed the approach while FO continued to fly. We decided not to declare an emergency and got vectors from ZZZ Approach for an uneventful approach and landing on Runway XXL. We taxied to parking on the ramp. Fire trucks met us at the gate and cleared the area after the source of the odor was determined and removed; and the associated attributes of the substance were reviewed. The box was labeled as Class 3 and had a shipping label for aromatic liquids/essential oils. The shipper was from ZZZZ. It was clearly wet at the bottom of the box.Dispatch had planned on us quick turning to ZZZ2; but FO had developed a headache and wanted to make sure it wasn't a result of the inhaled odors. Contacted Operations and eventually had trip revised for short layover in ZZZ. [The cause was] leaky HAZMAT. [I suggest] better packaging by shippers.