mcp-shell is an MCP server for running shell commands securely, auditably, and on demand. Prior to 0.6.0, config.go initializes Security.Enabled to false, and when MCP_SHELL_SEC_CONFIG_FILE is unset, main.go starts the documented bare-binary deployment without a security policy. SecurityValidator.validateCommand in security.go then short-circuits and allows every command supplied to the shell_exec MCP tool, so an LLM connected over stdio can execute unrestricted OS commands as the mcp-shell process user. The README from-source installation and MCP client configuration omit MCP_SHELL_SEC_CONFIG_FILE, making the insecure state the documented default.
This issue is fixed in version 0.6.0.
Attack Parameters
Attack Vector
Local
Requires local access
Attack Complexity
Low
Easy to exploit
Attack Requirements
None
No additional conditions
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed
Impact Assessment
Confidentiality
High
Complete data leak
Integrity
High
Complete data modification
Availability
High
Complete denial of service
CVSS Vector v4.0
Weakness Type (CWE)
Vulnerable Products
sonirico:mcp-shell
References 4
https://github.com/sonirico/mcp-shell/commit/f31377fce6ec31114e5a4398c0e5270552…
security-advisories@github.com
https://github.com/sonirico/mcp-shell/pull/16
security-advisories@github.com
https://github.com/sonirico/mcp-shell/releases/tag/v0.6.0
security-advisories@github.com
https://github.com/sonirico/mcp-shell/security/advisories/GHSA-f5pj-2738-996m
security-advisories@github.com