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://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!"