KB2844286 on SharePoint 2010 Breaks Web Parts

Came in to our project management site only to find several pages with data views (DVWP) throwing an error.

The logs have an error for each web part.

07/22/2013 10:20:26.95 w3wp.exe (0x2634) 0x2730 SharePoint Foundation Web Parts 89a1 High Error while executing web part: System.NullReferenceException: Object reference not set to an instance of an object. at System.Xml.Xsl.XslCompiledTransform.Load(MethodInfo executeMethod, Byte[] queryData, Type[] earlyBoundTypes) at Microsoft.Xslt.STransform.GetCompiledTransform() at Microsoft.SharePoint.WebPartPages.BaseXsltListWebPart.LoadXslCompiledTransform(WSSXmlUrlResolver someXmlResolver) at Microsoft.SharePoint.WebPartPages.DataFormWebPart.GetXslCompiledTransform() at Microsoft.SharePoint.WebPartPages.DataFormWebPart.PrepareAndPerformTransform(Boolean bDeferExecuteTransform) 3b2167ff-b5ed-4e4d-9797-87f715418136

Some googling turned up several articles about KB2844286 and SharePoint 2010.

http://techchucker.wordpress.com/2013/07/16/issue-kb2844286-security-update-on-sharepoint-2010/

http://social.msdn.microsoft.com/Forums/wpapps/en-US/871a0661-05d0-4f3a-b66d-2504552142bd/error-while-executing-web-part-systemnullreferenceexception-object-reference-not-set-to-an

http://social.technet.microsoft.com/Forums/sharepoint/en-US/6f5e2e94-e756-436f-af8e-68b5ca8a9290/error-while-executing-web-part-systeminvalidprogramexception-common-language-runtime-detected-an

http://sharepointeric.blogspot.com/2013/07/kb2844286-security-update-on-sharepoint.html

We are currently checking this out to see if it really fixes our issue…

…and the answer is "YES!"