LangBot is a global IM bot platform designed for LLMs. In version 4.10.7 and earlier, any authenticated user can add or change an STDIO MCP server configuration without an adequate authorization boundary. In src/langbot/pkg/provider/tools/loaders/mcp.py, StdioServerParameters accepts the configured command and arguments and starts a server-side subprocess on the LangBot server. An attacker who can sign up or obtain an account can use the Extensions MCP configuration to execute arbitrary commands with the privileges of the LangBot service, enabling data disclosure, modification, and service disruption. No fixed version is available as of this review.

CVE-2026-54449 affects LangBot, a global IM bot platform for LLMs, in versions 4.10.7 and earlier. Any authenticated user can add or modify an STDIO MCP server configuration without proper authorization controls. The vulnerable code in mcp.py uses StdioServerParameters to accept user-supplied commands and arguments, spawning server-side subprocesses. This allows any user who can register or obtain an account to execute arbitrary commands with the privileges of the LangBot service. The impact includes data disclosure, data modification, and service disruption. No fixed version is available as of the time of this review, making this an unpatched critical vulnerability in a widely used AI/LLM platform.