Notebook metadata is the embedded configuration stored inside a notebook file alongside the visible cells. It can describe kernels, rendering options, assistant integrations, execution settings, and other editor behavior. Unlike code cells, metadata may not be obvious to the user, yet it can still influence how the notebook opens and behaves.
This matters in cyber security because metadata can become part of the attack surface. If an editor trusts notebook metadata too early, a crafted file may trigger tool calls, launch helper processes, or alter workflow settings before a user runs any code. Defenders should treat third-party notebooks as potentially executable content: inspect metadata, open untrusted files in a constrained environment, and disable integrations that are not required. In practice, the lesson is simple: in notebook ecosystems, hidden configuration can be as sensitive as visible code.