Microsoft releases 11 Security Bulletins (MS15-032 through MS15-042) today, addressing a list of over 25 CVE-identified vulnerabilities for April of 2015. Critical vulnerabilities are fixed in Internet Explorer, Microsoft Office, and the network and graphics stacks. Most of the critical remote code execution (RCE) vulnerabilities reside in the IE memory corruption bugs for all versions of Internet Explorer (6-11) and the Microsoft Office use-after-free, however, they appear to all be result of private discoveries.
The Microsoft Office CVE-2015-1649 use-after free is a critical RCE impacting a variety of software and scenarios. The vulnerable code exists across desktop versions Word 2007, 2010, the Word Viewer and Office Compatibility apps, but not Word 2013 or Word for Mac. It's also critical RCE on the server-side in Word Automation Services on Sharepoint 2010 and Microsoft Office Web Apps Server 2010, but not SharePoint 2013 or Web Apps 2013.
As the new Verizon Data Breach 2015 report highlighted today, many exploits currently effective against targets are exploiting vulnerabilities patched long ago. According to their figures, many of the exploited CVE used on compromised hosts were published over a year prior. Microsoft provides Windows Update to easily keep your software updated, and Kaspersky products provide vulnerability scanners to help keep all of your software up-to-date, including Microsoft's. Please patch asap.
From the heap of vulnerabilities and fixes rated "Important", the Hyper-V DoS issue effects the newest Microsoft platform code: Windows 8.1 64-bit and Windows Server 2012 R2 (including the Server Core installation, which is fairly unusual). While the flawed code has not been found to enable EoP on other VMs within the Hyper-V host, attacked Hyper-V systems may lose management of all VMs in the Virtual Machine Manager.