PYSEC-2026-3472 jupyter-server is vulnerable to CORS origin validation bypass when the `allow_origin_pat` configuration is used

A vulnerability in jupyter-server versions 1.12.0 through 2.17.0 allows an attacker to bypass CORS origin validation when the alloworiginpat configuration is used. The issue arises from the use of re.match for validating the Origin header, which only anchors at the start of the string. This allow...