The Bavarians might be flying high in the UEFA Champions League with two wins out of two but their title defence in Germany has not got off to the best of starts.
Bayern Munich lost 1-0 away at Augsburg on Saturday, stretching their winless run in the top flight to four matches.
Nagelsmann's side have dropped to fifth on the table, five points behind surprise early pacesetters Union Berlin.
Having found themselves in an unfamiliar position on the table, there have been rumours of Nagelsmann's place coming under threat, with some reports suggesting former Chelsea manager Thomas Tuchel is waiting in the wings to take over should Bayern Munich decide to take action.
But Bayern CEO Kahn maintains Nagelsmann has his full backing despite admitting some concern over the club's poor form.
'We are not dealing with any other coaches now. We are totally convinced of Julian,' the former Bayern and Germany goalkeeper told Sky Germany.
'Of course we are all dissatisfied, in a bad mood.'
'We have to get to the bottom of it all. And assume that as soon as it starts again against Leverkusen, we will and must attack fully.'
'Perhaps one or the other has taken hold of the belief that you could do the Bundesliga on the side. But that's not the case.'
Bayern Munich will host Bayer Leverkusen in their next domestic game after the international break.
