openHAB, a provider of open-source home automation software, has add-ons including the visualization add-on CometVisu. Several endpoints in versions prior to 4.2.1 of the CometVisu add-on of openHAB don't require authentication. This makes it possible for unauthenticated attackers to modify or to steal sensitive data. This issue may lead to sensitive information disclosure. Users should upgrade to version 4.2.1 of the CometVisu add-on of openHAB to receive a patch.