CVE-2021-34473: Microsoft Exchange Server Remote Code Execution Vulnerability

Critical severity, CVSS 9.1. Actively exploited: in CISA KEV since 2021-11-03. EPSS: 100% chance of exploitation in the next 30 days.

Microsoft Exchange Server Remote Code Execution Vulnerability

Affected products

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

Published 2021-07-14. Last modified 2026-08-10.