CVE-2009-0561

CVE-2009-0561 describes an integer overflow vulnerability in Microsoft Excel across various Office versions, including Office 2000 through 2007, Office for Mac, and related viewers and compatibility packs. This flaw allows remote attackers to execute arbitrary code by crafting a malicious Excel file containing a malformed Shared String Table (SST) record, leading to a heap-based buffer overflow. With a CVSS score of 9.3, this vulnerability is critical, requiring no authentication and having high impact on confidentiality, integrity, and availability, though it requires user interaction (medium attack complexity). Despite its severity, there is no evidence of active exploitation, publicly available exploit code, or significant community discussion, and it is not listed in CISA's KEV catalog.