CVE-2021-43255: Microsoft 365 Apps

Medium severity, CVSS 5.5. EPSS: 2.1% chance of exploitation in the next 30 days.

Microsoft Office Trust Center Spoofing 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
• Microsoft Office Long Term Servicing Channel: version 2021 only

Published 2021-12-15. Last modified 2026-06-17.