CVE-2021-26858: Microsoft Exchange Server Remote Code Execution Vulnerability

High severity, CVSS 7.8. Actively exploited: in CISA KEV since 2021-11-03. EPSS: 93.7% 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 2021-03-03. Last modified 2026-10-01.