Jupyter server Token bruteforcing

Affects: Notebook and Lab between 6.4.0?potentially earlier and 6.4.11 currently latest. Jupyter Server =1.16.0. If I am correct about the responsible code it will affect Jupyter-Server 1.17.0 and 2.0.0a0 as well. Description: If notebook server is started with a value of rootdir that contains th...