IBM Langflow Docker MCP Server Volume-Mount Filtering Bypass
First seen Aug 5, 2026 · Updated Aug 5, 2026 · CVSS 8.8
IBM Langflow's handling of Docker-based MCP servers fails to properly filter dangerous volume-mount and device-mapping arguments, allowing an authenticated attacker to read, modify, or expose sensitive files on the host system. This is a high-severity flaw because it lets an already-authenticated but otherwise limited user escalate to host-level file access by abusing Langflow's MCP server tooling integration.
Technical Analysis
Langflow allows users to configure Docker-based MCP servers as tools within agent workflows, but the input validation for Docker run arguments (specifically volume mounts and device mappings) is incomplete. An authenticated attacker can supply crafted volume-mount or device-mapping parameters (e.g., mounting the host root filesystem or sensitive device nodes into the container) when configuring or invoking an MCP server tool. This crosses the container isolation boundary, granting the attacker read/write access to host files that should be inaccessible to the containerized MCP tool process, effectively turning a tool-integration feature into a host compromise vector. The vulnerability is exploitable via the normal agent-to-tool invocation path, meaning any workflow that permits configuring or triggering Docker-backed MCP servers is at risk.
Affected Systems
IBM Langflow OSS; protocols: MCP
Detection Signatures
- Docker run arguments containing '-v /' or '--mount type=bind,source=/' targeting root or sensitive host paths
- Device mapping flags (--device) referencing host device nodes (e.g., /dev/sda, /dev/mem)
- MCP server configuration payloads with unexpected absolute host paths in volume specifications
- Audit logs showing MCP server creation/modification by low-privilege authenticated users followed by container escapes
- Anomalous container mounts exposing /etc, /root, or Docker socket (/var/run/docker.sock)
Remediation Steps
- 1
Upgrade Langflow
Apply the vendor patch for CVE-2026-17626 as soon as it is available in a Langflow release beyond 1.10.3.
- 2
Restrict MCP server configuration privileges
Limit which authenticated users/roles can create or modify Docker-based MCP server tool configurations.
- 3
Enforce Docker run argument allowlisting
Implement strict server-side validation/allowlisting of volume-mount and device-mapping arguments, rejecting host-root or sensitive path mounts.
- 4
Run MCP containers with least privilege
Use rootless Docker, read-only filesystems, and drop unnecessary capabilities for MCP server containers.
- 5
Monitor container mount activity
Deploy runtime monitoring to detect and alert on containers mounting sensitive host paths or devices.
CVE / Advisory IDs
Industries Most Exposed
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