This vulnerability allows remote attackers to execute arbitrary code on vulnerable installations of Microsoft Office Excel. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file. The specific flaw exists within the handling of binary Excel files (.xlsb). By providing a malformed file, an attacker can cause a pointer to be re-used after it has been freed. An attacker could leverage this to execute arbitrary code under the context of the current user.