Vulnerability in MCP Context Forge's Python Sandbox Server Allows Command Execution

CVE-2026-53710

What is CVE-2026-53710?

The MCP Context Forge's python_sandbox_server component prior to version 1.0.2 is vulnerable to command execution. This vulnerability arises from the exposure of raw getattr through safe_builtins, without a necessary guard on getattr. Consequently, an attacker can manipulate dunder names at runtime, traversing the Python class hierarchy to gain access to subprocess.Popen, enabling them to execute operating system commands with the privileges of the server process. This vulnerability can be exploited via the HTTP/SSE transport, which may expose the execute_code MCP tool without authentication, while stdio-only deployments offer limited network reachability. The issue is specific to the python_sandbox_server subcomponent and does not implicate the main Context Forge gateway or proxy functionalities. To mitigate the risks, users are advised to update to version 1.0.2 or later.

References