mcp-shell is an MCP server for running shell commands securely, auditably, and on demand. Prior to 0.6.0, the default Docker security.yaml includes /bin/bash in allowed_executables, while security.go validates only the first token and checkBlockedPatternsAndCommands does not reject the shell command-mode flag -c. A caller of the shell_exec MCP tool can provide the command argument `/bin/bash -c <arbitrary-command>`, which passes validation and reaches executor.go, where parseCommand and exec.CommandContext execute the arbitrary command as mcpuser outside the intended allowlist.
This issue is fixed in version 0.6.0.
Attack Parameters
Attack Vector
Local
Requires local access
Attack Complexity
Low
Easy to exploit
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 v3.1
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-3x77-wg38-92r3
security-advisories@github.com