Summary
A command injection vulnerability in Langflow's MCP stdio transport allows attacker-controlled server configurations to launch arbitrary operating system commands on the Langflow host. The risk is especially severe on exposed instances with automatic login enabled, while authenticated non-administrative users may also be able to trigger command execution when that setting is disabled.
A command injection vulnerability in Langflow's MCP stdio transport allows attacker-controlled server configurations to launch arbitrary operating system commands on the Langflow host. The risk is especially severe on exposed instances with automatic login enabled, while authenticated non-administrative users may also be able to trigger command execution when that setting is disabled.
Affected context
The vulnerability occurs in Langflow deployments that use the MCP server configuration or MCP Tools component with the stdio transport. It becomes risky when a user can create or modify MCP server settings, or otherwise cause Langflow to connect to a configured server, and the deployment permits arbitrary command values to reach the host process launcher.
The vulnerability occurs in Langflow deployments that use the MCP server configuration or MCP Tools component with the stdio transport. It becomes risky when a user can create or modify MCP server settings, or otherwise cause Langflow to connect to a configured server, and the deployment permits arbitrary command values to reach the host process launcher.
Exploit preconditions
- Attack surface: Langflow MCP server settings, MCP API endpoints, and flows using the MCP Tools component
- Required access: Unauthenticated access may be sufficient when automatic login is enabled; otherwise, an authenticated user with relevant configuration or flow access may be sufficient
- Trigger point: Langflow attempts to connect to, list, load tools from, or run a flow involving an MCP stdio server
- Why exploitation is possible: User-controlled command and argument values are passed to an operating system shell or process launcher without an effective allowlist or equivalent restriction
- Attack surface: Langflow MCP server settings, MCP API endpoints, and flows using the MCP Tools component
- Required access: Unauthenticated access may be sufficient when automatic login is enabled; otherwise, an authenticated user with relevant configuration or flow access may be sufficient
- Trigger point: Langflow attempts to connect to, list, load tools from, or run a flow involving an MCP stdio server
- Why exploitation is possible: User-controlled command and argument values are passed to an operating system shell or process launcher without an effective allowlist or equivalent restriction
Why this happens
The issue is an OS command injection flaw mapped to CWE-78. Langflow treated MCP server command configuration as executable process input and, in affected behavior, routed it through shell command construction without constraining the executable to approved programs. This creates a direct path from configuration data to operating system command execution instead of maintaining a strict separation between data and process invocation.
The issue is an OS command injection flaw mapped to CWE-78. Langflow treated MCP server command configuration as executable process input and, in affected behavior, routed it through shell command construction without constraining the executable to approved programs. This creates a direct path from configuration data to operating system command execution instead of maintaining a strict separation between data and process invocation.
Potential impact
- Arbitrary commands may execute with the privileges of the Langflow process
- The Langflow host or container could be compromised
- Application data, credentials, and workflow definitions could be exposed or altered
- An attacker could establish persistence or use the host for lateral movement
- Integrity of AI agents, tools, and downstream workflows could be undermined
- Service availability could be disrupted
- Arbitrary commands may execute with the privileges of the Langflow process
- The Langflow host or container could be compromised
- Application data, credentials, and workflow definitions could be exposed or altered
- An attacker could establish persistence or use the host for lateral movement
- Integrity of AI agents, tools, and downstream workflows could be undermined
- Service availability could be disrupted
General mitigation guidance
Mitigation generally focuses on preventing user-controlled values from becoming arbitrary operating system commands.
Common defensive patterns include:
- Use a strict allowlist of approved MCP executables and validated argument formats
- Invoke processes directly with structured argument arrays rather than shell command strings
- Avoid shell interpretation and shell wrappers for configurable process launches
- Restrict MCP server creation and modification to trusted administrative workflows
- Disable development-only automatic authentication in production environments
- Run Langflow with a dedicated, least-privileged operating-system identity
- Isolate worker processes and limit filesystem, network, and secret access
- Apply server-side authorization and validation consistently across UI, API, and flow execution paths
Mitigation generally focuses on preventing user-controlled values from becoming arbitrary operating system commands.
Common defensive patterns include:
- Use a strict allowlist of approved MCP executables and validated argument formats
- Invoke processes directly with structured argument arrays rather than shell command strings
- Avoid shell interpretation and shell wrappers for configurable process launches
- Restrict MCP server creation and modification to trusted administrative workflows
- Disable development-only automatic authentication in production environments
- Run Langflow with a dedicated, least-privileged operating-system identity
- Isolate worker processes and limit filesystem, network, and secret access
- Apply server-side authorization and validation consistently across UI, API, and flow execution paths
How teams detect issues like this
Detection can combine source review, runtime monitoring, and policy enforcement:
- Use static analysis to identify shell invocation APIs, command interpolation, and process launchers receiving configuration-derived values
- Review MCP transport code for missing executable allowlists and inconsistent validation between UI and API paths
- Monitor process creation from the Langflow service for unexpected binaries, shell interpreters, or unusual child-process activity
- Audit MCP configuration changes and correlate them with process starts and flow execution
- Enforce policies that prevent production services from enabling unauthenticated or development-only access modes
- Use automated code review and dependency security tooling to flag command construction and unsafe process execution patterns
Detection can combine source review, runtime monitoring, and policy enforcement:
- Use static analysis to identify shell invocation APIs, command interpolation, and process launchers receiving configuration-derived values
- Review MCP transport code for missing executable allowlists and inconsistent validation between UI and API paths
- Monitor process creation from the Langflow service for unexpected binaries, shell interpreters, or unusual child-process activity
- Audit MCP configuration changes and correlate them with process starts and flow execution
- Enforce policies that prevent production services from enabling unauthenticated or development-only access modes
- Use automated code review and dependency security tooling to flag command construction and unsafe process execution patterns
