CVE-2021-31178: Microsoft 365 Apps

Medium severity, CVSS 5.5. EPSS: 16% chance of exploitation in the next 30 days.

Microsoft Office Information Disclosure Vulnerability

Affected products

• Microsoft 365 Apps: affected versions not specified
• Microsoft Excel: version 2013 only; version 2016 only
• Microsoft Office: version 2013 only; version 2016 only; version 2019 only
• Microsoft Office Online Server: affected versions not specified
• Microsoft Office Web Apps Server: version 2013 only
• Microsoft Word: version 2013 only; version 2016 only

Published 2021-05-11. Last modified 2026-06-17.