The issue is caused by an out-of-bounds access in memory, allowing a remote attacker to execute arbitrary code using a specially crafted XLS file. Exploitation of the vulnerability requires a user to open the malicious file with an affected version of Microsoft Excel. If successfully exploited, an attacker could run arbitrary code in the context of the current user, potentially taking control of the affected system, installing programs, viewing, changing, or deleting data, or creating new accounts with full user rights.