Executive brief
eiceblue spire-doc-mcp-server is a tool that allows AI agents to interact with Word documents. A security flaw in the document conversion feature allows a remote attacker to save files to unauthorized locations on the server's file system. This could lead to the overwriting of sensitive system files or the placement of malicious data outside of the intended document directory.
Technical details
A path traversal vulnerability exists in eiceblue spire-doc-mcp-server 1.0.0 within the conversion API. While the 'document_name' parameter is validated via get_doc_path(), the 'output_path' parameter in the convert_document function (located in src/spire_doc_mcp/server.py and processed in conversion_tools.py) is passed directly to the file-saving routine without canonicalization or boundary enforcement. A remote attacker can exploit this by providing a path containing traversal sequences (e.g., ../) to create or overwrite files anywhere the service account has write permissions. As of the advisory date, no official patch has been released by the vendor.
Affected products
- eiceblue spire-doc-mcp-server 1.0.0
Timeline
- 2026-04-10: other: Vulnerability discovered via static analysis
- 2026-04-12: disclosed: Issue reported on GitHub repository
- 2026-04-28: advisory: NVD/VulDB advisory published