CVE-2017-5159: Phoenixcontact Mguard Firmware

Critical severity, CVSS 9.8. EPSS: 2.4% chance of exploitation in the next 30 days.

An issue was discovered on Phoenix Contact mGuard devices that have been updated to Version 8.4.0. When updating an mGuard device to Version 8.4.0 via the update-upload facility, the update will succeed, but it will reset the password of the admin user to its default value.

Affected products

Published 2017-02-13. Last modified 2026-06-17.