CVE-2020-26215: Open redirect in Jupyter Notebook

What kind of vulnerability is it? Who is impacted?

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.