CVE-2021-40454: Microsoft 365 Apps

Medium severity, CVSS 5.5. EPSS: 0.5% chance of exploitation in the next 30 days.

Rich Text Edit Control Information Disclosure Vulnerability

Affected products

• Microsoft 365 Apps: affected versions not specified
• Microsoft Office: version 2013 only; version 2013_rt only; version 2016 only; version 2019 only; version 2021 only
• Microsoft Windows 10: affected versions not specified; version 20h2 only; version 21h1 only; version 1607 only; version 1809 only; version 1909 only; …
• Microsoft Windows 11: affected versions not specified
• Microsoft Windows 8.1: affected versions not specified
• Microsoft Windows Rt 8.1: affected versions not specified
• Microsoft Windows Server: version 20h2 only; version 2004 only
• Microsoft Windows Server 2012: affected versions not specified; version r2 only
• Microsoft Windows Server 2016: affected versions not specified
• Microsoft Windows Server 2019: affected versions not specified
• Microsoft Windows Server 2022: any version

Published 2021-10-13. Last modified 2026-06-17.