Microsoft released two patches on Tuesday, one of them critical, as part of its regular Patch Tuesday update cycle.
The critical update (MS11-035) affects the WINS component of Windows 2003 and 2008 Server operating systems. WINS resolves names in the NetBIOS namespace in much the same way as DNS resolves names to IP addresses on the web. It is not enabled by default. Exploitation of the flaw would most likely come in the form of denial of service attacks, according to security patching outfit Qualys.
The second "important" update (MS11-036) affects older versions of Microsoft Office PowerPoint. Left unpatched, the flaw creates a means to plant malware in specially malformed PowerPoint files, making the vulnerability particularly useful in targeted attack. Users of Office XP, 2003, 2007 and 2004 for Mac are all potentially at risk from the vulnerability.
The modest two-bulletin brace this month follows a bumper crop of 17 updates in April and continues Microsoft's practice of alternating smaller and larger patch batches.
Microsoft only patched Windows version of vulnerable flavours of PowerPoint. Mac users, except user of Microsoft Office for Mac (2011) - which is immune, were left in the lurch. More details on this aspect of the story from a blog post by Sophos here.