// Microsoft 365CRITICAL
CVE-2026-81951 is a critical heap-based buffer overflow in Microsoft Excel affecting Microsoft 365 Apps, Office 2016, 2019, LTSC 2021/2024, and Office for Mac. The vulnerability requires user interaction (opening a malicious Office file) but enables local code execution with high impact to confidentiality, integrity, and availability. Microsoft released fixes on September 24, 2026. Exploitation has not been observed in the wild, but the breadth of affected installations makes rapid patching a priority.
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