Someone has breached a Microsoft server, giving him access to beta-products and activation keys of those products. He wasn't able to get any source code.

The server in question houses Microsoft beta-products, and has about 20,000 user, testing that software. Microsoft states:

They are not grabbing code; they are grabbing product, and it's going to be buggy and it's going to have problems," he said. "This is obviously not good, but it's not terrible either.
Source: CNet