iTunes 11.0.4 has been released, the update is fairly minor and focuses on fixing a few prominent bugs. Notably, a bug that caused users to have to frequently re-login to the iTunes Store has been squashed, and the update also resolves an issue that caused iTunes to quit after switching between wired and wireless syncing for iOS devices.
As of now, the releases notes accompanying the download are the same as those that came with iTunes 11.0.3, with a small addition to the bottom which discusses the two aforementioned bugs.
iTunes 11.0.4 can be downloaded now from the Mac App Store, or by going to the Software Update option from the Apple menu. A direct download weighing in at 188MB is also available from Apple’s website for both Mac OS X and Windows users, that can be downloaded from here.