CVE-2026-111057

Affected versions of the `mercury` package are vulnerable to Missing Authentication for Critical Function due to a missing comma in the endpoint blocklist that leaves the Jupyter terminal API reachable without authentication. In `mercury_app/block_handler.py`, the `/lab` pattern and the `/api/terminals` pattern of `BLOCKED_PATTERNS` have no comma between them, so Python joins the two strings into a single regular expression that matches neither endpoint on its own, and a direct request to `/api/terminals` reaches Jupyter Server's built-in terminal handler on a server that runs with an empty token by default. An unauthenticated attacker who can reach a Mercury server can send `POST /api/terminals` to spawn a terminal and then connect to its websocket to run arbitrary operating system commands with the privileges of the Mercury process, gaining full control of the host or container.