Command Execution Flaw in MCP Shell Server by Sonirico

CVE-2026-55582

What is CVE-2026-55582?

The mcp-shell server, which facilitates the secure execution of shell commands, contains a significant command injection vulnerability due to improper security configurations prior to version 0.6.0. Specifically, the default configuration permits the execution of arbitrary commands via the Git command alias functionality. An attacker can exploit this by issuing a command to the shell_exec MCP tool, allowing manipulation of the Git alias to execute arbitrary OS commands as the mcp-shell user. This vulnerability is particularly concerning when using the default Docker implementation, which operates as the user 'mcpuser' and has Git installed, making this exploit feasible without stringent authentication measures. The issue has been remedied in version 0.6.0, which is recommended for all users.

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