A stack-based buffer overflow in Microsoft Office Excel enables an attacker to execute arbitrary code when a user opens a malicious spreadsheet. The flaw permits the attacker to run code with the privileges of the user, compromising confidentiality, integrity, and availability of the affected system. The vulnerability is a classic memory corruption issue, classified under CWE-121 for stack-based buffer overflow.

The flaw affects multiple Microsoft Office product lines, including Microsoft 365 Apps for Enterprise, Microsoft Office 2021 LTSC, Microsoft Office 2024 LTSC, Office 365 for Mac, Office LTSC for Mac 2021, Office LTSC for Mac 2024, and Office Online Server. No specific version restrictions are listed beyond the general support of these product families.

The CVSS score of 8.8 indicates a high severity issue. Exploitation probability is currently unknown due to the absence of an EPSS metric, and the vulnerability is not flagged in the CISA KEV catalog, suggesting no publicly documented exploits at the time of analysis. Attackers would likely deliver malicious files over a network, such as via email or a shared drive, and exploit the buffer overflow when the spreadsheet is opened. The high severity and remote nature of the attack vector make it a priority for remediation.