CVE-2026-21258 MEDIUM

CVE-2026-21258: Microsoft Excel Information Disclosure Vulnerability

Vendor Microsoft
Product Microsoft 365 Apps for Enterprise
Weakness CWE-20 · Input validation
Published February 10, 2026
Last update May 11, 2026
View on NVD All CVEs

CVSS base score

5.5/10
Attack vector Local
Attack complexity Low
Privileges required None
User interaction Required
Confidentiality High
Integrity None

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C

What the vulnerability does

01Description

Improper input validation in Microsoft Office Excel allows an unauthorized attacker to disclose information locally.

Key dates

02Disclosure timeline

February 10, 2026 CVE published
May 11, 2026 Record updated