CVE-2026-49357

# Streamable HTTP mode exposes LINE Desktop read/send tools without MCP authentication ## Summary `line-desktop-mcp` supports a `--http-mode` Streamable HTTP transport for use with clients such as n8n. In this mode the server binds to `0.0.0.0` and exposes the MCP `/mcp` endpoint without an MCP-layer authentication check. Any network client that can reach the port can initialize a session, list tools, and call tools that read LINE Desktop chat history or send LINE messages through the already logged-in desktop application. This is High for deployments where the HTTP port is reachable beyond the local host, because the server acts with the user authority of the logged-in LINE Desktop session. It is lower if the listener is strictly firewalled to trusted local clients. ## Affected version Repository: `dtwang/line-desktop-mcp` Current source checked: `fbed0d2d3048e63f48a356a1267ed8ec5e78f3ae` on `main`, committed 2026-05-14. Published npm package checked: `[email protected]`. ## Source evidence `README.md` documents Streamable HTTP mode: ```text npx line-desktop-mcp@latest --http-mode --port 3000 ``` The same README documents MCP endpoints at `/mcp` and explains that this mode is intended for clients such as n8n. `src/server.js` registers LINE Desktop tools including: - `get_line_chatroom_history_default` - `get_line_chatroom_history_long` - `get_line_chatroom_history_short` - `send_message_manual` - `send_message_auto` Those tool handlers call into the desktop automation layer: `getChatHistory(...)` and `sendChatMessage(...)`. In HTTP mode, `src/server.js` creates an Express app and Streamable HTTP transport, accepts POSTs to `/mcp`, creates sessions, connects the transport to the MCP server, and calls `transport.handleRequest(...)`. I did not find an authentication or bearer-token check before session creation or tool invocation. The listener is explicitly network-bound: ```js app.listen(port, 0.0.0.0, () => { console.error(`LINE Desktop MCP S