IBM Langflow OSS 1.0.0 through 1.11.5 allows an authenticated non-administrative user could execute arbitrary operating system commands on the server at the privilege level of the application process by constructing a flow with an MCP Tools component configured to use a local stdio subprocess transport. This bypasses both the LANGFLOW_CUSTOM_COMPONENT_ADMIN_ONLY and LANGFLOW_BLOCK_CODE_INTERPRETER_COMPONENTS server-side controls intended to prevent exactly this class of access. Successful exploitation could lead to arbitrary command execution, sensitive data exposure (including credentials from the process environment), file system modification, and lateral movement to services reachable from the server.
IBM strongly recommends addressing the vulnerability now by upgrading Langflow OSS to version 1.11.6 https://pypi.org/project/langflow/