Jupyter Notebook before version 6.1.5 has an Open redirect vulnerability. A maliciously crafted link to a notebook server could redirect the browser to a different website. All notebook servers are technically affected, however, these maliciously crafted links can only be reasonably made for known notebook server hosts. A link to your notebook server may appear safe, but ultimately redirect to a spoofed server on the public internet. The issue is patched in version 6.1.5.
https://lists.debian.org/debian-lts-announce/2020/12/msg00004.html
https://github.com/jupyter/notebook/security/advisories/GHSA-c7vm-f5p4-8fqh
https://github.com/jupyter/notebook/commit/3cec4bbe21756de9f0c4bccf18cf61d840314d74