A vulnerability classified as critical was found in Viessmann Vitogate 300 up to 2.1.3.0. This vulnerability affects the function isValidUser of the file /cgi-bin/vitogate.cgi of the component Web Management Interface. The manipulation leads to use of hard-coded password. The exploit has been disclosed to the public and may be used. The identifier of this vulnerability is VDB-240364. NOTE: The vendor was contacted early about this disclosure but did not respond in any way.