MCP Documentation Server: Web UI API binds to all interfaces without authentication by default

Summary

MCP Documentation Server is a local-first document management and semantic search server for AI coding agents. From 1.13.0 until 1.13.1, the automatically started Web UI in src/server.ts calls startWebServer in src/web-server.ts with START_WEB_UI enabled by default and WEB_PORT set to 3080. startWebServer uses app.listen(PORT) without a host, which binds the unauthenticated document-management API to all interfaces rather than localhost. A network-reachable client can invoke GET /api/documents, GET /api/documents/:id, POST /api/documents, POST /api/search-all, DELETE /api/documents/:id, and GET /api/config without credentials to enumerate and read documents, search the corpus, insert or delete documents, and tamper with the MCP assistant's knowledge base. The service must be reachable from the attacker's LAN, VM network, container bridge, VPN, or another routed network, and the issue does not provide remote code execution. This issue is fixed in 1.13.1.

Timeline

1. Sep 17, 2026, 6:36 PM UTCCVE published
2. Sep 17, 2026, 7:09 PM UTCCISA SSVC assessment

   Exploitation: poc · Automatable: no · Technical impact: total

3. Sep 17, 2026, 7:09 PM UTCRecord last updated

Affected versions

• andrea9293 mcp-documentation-server

  From 1.13.0 · fixed in 1.13.1

• @andrea9293/mcp-documentation-servernpm

  From 1.13.0 · fixed in 1.13.1

References 4