News

Excel Patch Causing Calculation Errors

Microsoft admitted on Friday that a patch it released last week is causing Excel 2003 to make some incorrect calculations.

• By Becky Nagel
• March 17, 2008

"We have updated bulletin MS08-014 to provide additional information on a newly identified issue that causes Microsoft Excel 2003 calculations to return an incorrect result when a Real Time Data source is used," Microsoft's Security Response Center's Bill Sisk wrote in a blog post last week.

"The issue affects a specific scenario and may not affect you...Our teams are testing a fix and will release it once it meets our quality bar for broad distribution," he continued.

Microsoft offers some insight into the problem in Knowledge Base (KB) article 950340. According to the KB, after the patch is applied on systems with "Microsoft Office Excel 2003 installed, array-entered functions that contain a Visual Basic for Applications (VBA) macro that refers to a Real Time Data source return an incorrect value. The incorrect value is usually 0."

According to the very short KB item, for a current workaround, Microsoft recommends, "Run the function on each cell individually instead of on the array of cells."

The only other information available in the KB is that Microsoft is working on a fix and will post more information as it becomes available.

The patch was released last week to stop versions of Excel from allowing several types of remote execution attacks.