Integer underflow in Microsoft Excel 2002 SP3, 2003 SP3, 2007 SP2, and 2010; Office 2004 and 2008 for Mac; Open XML File Format Converter for Mac; Excel Viewer SP2; and Office Compatibility Pack for Word, Excel, and PowerPoint 2007 File Formats SP2 allows remote attackers to execute arbitrary code via a crafted 400h substream in an Excel file, which triggers a stack-based buffer overflow, aka "Excel Integer Overrun Vulnerability."