What happened
The _validate_file_path function in mcp_text_editor/text_editor.py (tumf/mcp-text-editor, an MCP server for text file editing) is vulnerable to path traversal via the file_path argument, allowing remote manipulation to escape the intended directory. A public exploit is reported to exist.
Why it matters
This is an MCP tool-surface path traversal in a text-editing MCP server callable by LLM agents; while single-author/niche, it exemplifies the recurring pattern of insufficient path-boundary validation across the MCP server ecosystem, and a public exploit increases near-term risk for any agent deployment using this server.
Attack vector
Crafted file_path argument to MCP text-editor tool escapes intended directory boundary via path traversal
Affected systems
tumf mcp-text-editor ≤ 1.0.2
Mitigation
Update to a patched version once available; restrict MCP server filesystem access via containerization or chroot