CVE-2021-41028: Fortinet FortiClient

High severity, CVSS 7.5. EPSS: 0.2% chance of exploitation in the next 30 days.

A combination of a use of hard-coded cryptographic key vulnerability [CWE-321] in FortiClientEMS 7.0.1 and below, 6.4.6 and below and an improper certificate validation vulnerability [CWE-297] in FortiClientWindows, FortiClientLinux and FortiClientMac 7.0.1 and below, 6.4.6 and below may allow an unauthenticated and network adjacent attacker to perform a man-in-the-middle attack between the EMS and the FCT via the telemetry protocol.

Affected products

• Fortinet FortiClient: from 6.0.0, up to and including 6.0.9; from 6.2.0, up to and including 6.2.9; from 6.4.0, up to and including 6.4.6; version 7.0.0 only; version 7.0.1 only
• Fortinet FortiClient Endpoint Management Server: from 6.2.0, up to and including 6.2.9; from 6.4.0, up to and including 6.4.6; version 7.0.0 only; version 7.0.1 only

Published 2021-12-16. Last modified 2026-06-17.