CVE-2021-3547: Openvpn

High severity, CVSS 7.4. EPSS: 1.2% chance of exploitation in the next 30 days.

OpenVPN 3 Core Library version 3.6 and 3.6.1 allows a man-in-the-middle attacker to bypass the certificate authentication by issuing an unrelated server certificate using the same hostname found in the verify-x509-name option in a client configuration.

Affected products

• Openvpn Openvpn: version 3.6 only; version 3.6.1 only

Published 2021-07-12. Last modified 2026-06-17.