Tannic acid in oak can accelerate the process, especially for older figures, which may have higher lead content, and may have exposed surface area (like the inside of a hollowcast figure-that's all surface, too, and exposed to the air). It can vaporize as the wood expands and contracts with changes in temperature, and if there is high humidity, it can join with water vapor to make an atomized solution, that can come to rest on any surface.
If the wood is sealed, and if your cabinets are in a climate-controlled room, where there are not wide variations in temperature and humidity, that will help reduce the odds that the lead will rot. For newer figures, it's not as much of an issue, because most manufacturers have gotten away from alloys with higher lead content, and many figures have a primer or undercoat that seals all surfaces from exposure to the air.
Prost!
Brad