This indicates an attack attempt against a heap-overrun vulnerability in Microsoft Publisher.
The vulnerability exists in the way that Microsoft Publisher parses specially crafted Publisher files. It allows an attacker to execute arbitrary code by sending a specially crafted Publisher file to the user and by convincing the user to open the file.
Microsoft Office XP Service Pack 3
Microsoft Office 2003 Service Pack 3
Microsoft Office 2007 Service Pack 2
Microsoft Office 2010 (32-bit editions)
Microsoft Office 2010 (64-bit editions)
System Compromise: Remote attackers can gain control of vulnerable systems.
Apply the patch, available at the vendor's website: