DeepTutor missing MCP tool authorization allows non-admin users to invoke unrestricted tools

DeepTutor before version 1.4.10 contains an authorization bypass vulnerability that allows low-privilege users to invoke unrestricted MCP tools due to the allowed_mcp_tools function returning None instead of a denied result when mcp_tools is omitted from a user's grant in deeptutor/multi_user/tool_access.py. Attackers or prompt-injected content acting within a user session can enumerate and invoke any configured MCP tool, including filesystem, shell, and browser servers, gaining unauthorized access to sensitive deployment resources.