CVE-2026-55037 Details

A heap-based buffer overflow vulnerability has been identified in Microsoft Office Excel. This vulnerability allows an unauthorized attacker to execute code locally. It affects multiple versions of Microsoft Excel, including Excel 2016 (both 32-bit and 64-bit editions), Excel 2019 (32-bit and 64-bit editions), and various editions of Microsoft Office LTSC and Microsoft 365 Apps for Enterprise, both for Mac and Windows. The vulnerability requires user interaction, as an attacker must send a malicious Office file and convince the user to open it.

Users can download the security update for this vulnerability through the Microsoft Update Catalog or via the Microsoft 365 Apps security update channel. For Office LTSC for Mac 2021 and 2024, the security update is also available through the Mac App Store.