Advisories for Golang/Github.com/Sonirico/Mcp-Shell package

mcp-shell's "secure mode" is designed to restrict command execution to an allowlist of executables defined in security.yaml. The default configuration includes /usr/bin/git. The security validator in security.go blocks common shell metacharacters (|&;<>(){}[]$``) but omits !, which is the prefix Git uses to execute shell aliases (alias.NAME=!CMD). An attacker who can invoke the shell_execMCP tool can pass/usr/bin/git -c alias.pwn=!as the command argument, bypassing all validation and achieving arbitrary OS command execution …

mcp-shell ships a default Docker configuration (security.yaml) that includes /bin/bash in the allowed_executables allowlist. The command validator (security.go) only checks whether the first token of the supplied command matches an allowed executable; it does not inspect or reject shell command-mode flags such as -c. As a result, any MCP tool caller can send command=/bin/bash -c <arbitrary-command> to the shell_exec tool and execute commands that are not in the allowlist — …

mcp-shellat commit17ac0eef5c9a5a42b8fb132d3d034973d55a5433` has two issues that together mean neither the default deploy path nor the recommended "secure mode" delivers the restriction they're marketed as providing. Filing these together because the two failure modes bracket the full intended audience — the from-source path gets users who skip security config entirely, the Docker path gets users who follow the security.yaml example and believe they're protected. The first issue is in config.go, line …