cve 2026 55898

The cve 2026 55898 tag covers Microsoft’s security update for an information-disclosure vulnerability in Microsoft Excel. The flaw is an out-of-bounds memory read that could expose data when a user interacts with malicious content. Coverage includes the affected supported Windows and macOS editions of Office and Office Online Server, along with Microsoft’s KB5002886 update guidance. The vulnerability carries an Important severity rating and a CVSS 3.1 score of 6.1. Microsoft assessed exploitation as less likely and reported no public disclosure or active exploitation when the update was released. This archive provides a focused reference for understanding the issue, affected products, and recommended patch response.