CVE-2026-54449 in LangBot
Summary
by MITRE • 08/20/2026
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.
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Analysis
by VulDB Data Team • 08/20/2026
The vulnerability identified in LangBot versions 4.10.7 and earlier represents a critical authorization bypass within its Model Context Protocol (MCP) integration layer. LangBot serves as an interface for Large Language Models to interact with external tools, including STDIO MCP servers which allow the execution of local commands via subprocesses. The core technical flaw resides in the src/langbot/pkg/provider/tools/loaders/mcp.py module, specifically within the StdioServerParameters class. This component is responsible for accepting configuration parameters such as command strings and their associated arguments from user input to instantiate a server-side subprocess. However, the implementation lacks adequate authorization boundaries when processing these configurations. Consequently, any authenticated user, regardless of their role or privilege level, can manipulate this endpoint to define arbitrary commands that will be executed by the LangBot service process itself.
This architectural deficiency allows an attacker who has obtained valid credentials through sign-up or other means to escalate privileges effectively from a standard user account to full control over the underlying operating system environment where the LangBot instance is running. By injecting malicious command sequences into the MCP configuration, the attacker can execute arbitrary shell commands with the same permissions as the service account. This capability transforms what might appear as a simple configuration error into a severe remote code execution vector. The impact extends beyond mere process manipulation; it enables comprehensive data disclosure by allowing attackers to read sensitive files stored on the server, facilitates data modification through write operations or file system alterations, and permits service disruption via denial-of-service techniques such as resource exhaustion or killing critical processes.
From a classification perspective, this vulnerability aligns with CWE-269, which denotes Improper Privilege Control, specifically highlighting the failure to enforce proper authorization checks for administrative functions. Furthermore, it maps directly to MITRE ATT&CK technique T1059 Command and Scripting Interpreter, as the attacker utilizes system commands through a legitimate application interface to achieve malicious objectives. The absence of input validation or role-based access control on the endpoint that accepts STDIO MCP configurations creates an open channel for exploitation. Since no fixed version is available at the time of this review, organizations relying on LangBot must implement immediate compensating controls. These may include restricting network access to the LangBot interface to trusted IP ranges only, running the service in a highly restricted container or sandbox with minimal file system permissions, and monitoring subprocess creation events for anomalies indicative of unauthorized command execution until an official patch is released by the vendor.