Relatively little is known about the Malon; there has been no formal contact with the Malon government as such, merely a series of accidental encounters with their ships. Since these encounters have occurred over thirty thousand light years apart, it is possible that Malon territory extends across these kinds of distances - making their space far larger than the Federation. However, the Malon are known to have access to at least one stable "spatial vortex" - apparently a form of wormhole. It is possible that they have access to others which allow them to cross large distances, or even that are able to build such phenomena themselves. At this point in time we simply do not know.