CVE-2017-5159: An issue was discovered on Phoenix Contact mGuard devices that have been updated to Version 8.4.0.

Security readout for executives and security teams

Phoenix Contact mGuard devices updated to Version 8.4.0 through the update-upload facility could have the admin password reset to its default value. If not corrected immediately, a security gateway may be left with predictable administrator access after a successful update. Exposure appears limited to Phoenix Contact mGuard devices updated to Version 8.4.0 via the update-upload facility. Risk is highest where administrative access is reachable from untrusted networks or where post-upgrade password checks were not performed. Treat this as a priority operational exposure for any environment using mGuard security devices. The issue can leave administrative access predictable after an update, but evidence in the bundle does not show broad exploitation or a quantified severity score. Mitigation focus: Identify any Phoenix Contact mGuard devices updated to Version 8.4.0.; Immediately verify and change the admin password after affected updates.; Restrict administrative access to trusted management networks only..

Prepared

Jun 13, 2026, 06:20 UTC (UTC+00:00)

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.