[GHSA] GHSA-74hp-mggr-hv58 (high) — mcp-shell has a Secure Mode Allowlist Bypass via Git Shell Alias

GHSA-74hp-mggr-hv58 Severity: high CVE: CVE-2026-55582

mcp-shell has a Secure Mode Allowlist Bypass via Git Shell Alias

### Summary

`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 (`|&;<>(){