CVE-2021-31207: Microsoft Exchange Server Security Feature Bypass Vulnerability

Medium severity, CVSS 6.6. Actively exploited: in CISA KEV since 2021-11-03. EPSS: 99.8% chance of exploitation in the next 30 days.

Microsoft Exchange Server Security Feature Bypass Vulnerability

Affected products

• Microsoft Exchange Server: version 2013 only; version 2016 only; version 2019 only

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