It was just last week that build 7955 leaked to the Internet, but now, according to BetaArchive, build 7959 has been leaked. This build represents the first M3 build to be leaked but is said to be quite buggy. It should be noted that this is a server build, unlike the previous leak, 7955, which was of the Ultimate variety. This build weighs in at 2.87GB and is said to be an X64 build.
Previously, Neowin has covered information that leaked out from previous Windows 8 leaks which can be viewed here. As this is a later build, it is expected that users will be able to unlock features that have previously not been seen.
Windows 8 is far off from public availability and it is rumored that a public beta may be announced at PDC later this year. It is expected that Microsoft will launch Windows 8 in late 2012 with the latest rumors suggesting that retail availability will happen in early 2013.