jupyter-server is the backend for Jupyter web applications. Improper cross-site credential checks on `/files/` URLs could allow exposure of certain file contents, or accessing files when opening untrusted files via "Open image in new tab". This issue has been addressed in commit `87a49272728` which has been included in release `2.7.2`. Users are advised to upgrade. Users unable to upgrade may use the lower performance `--ContentsManager.files_handler_class=jupyter_server.files.handlers.FilesHandler`, which implements the correct checks.
https://github.com/jupyter-server/jupyter_server/security/advisories/GHSA-64x5-55rw-9974
https://github.com/jupyter-server/jupyter_server/commit/87a4927272819f0b1cae1afa4c8c86ee2da002fd