Vulnerabilities in pkg:npm/line-desktop-mcp

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-4hf8-5mjm-rfgq",
  "modified" : "2026-06-26T21:50:50Z",
  "published" : "2026-06-26T21:50:49Z",
  "aliases" : [ "CVE-2026-49357" ],
  "summary" : "Streamable HTTP mode exposes LINE Desktop read/send tools without MCP authentication",
  "details" : "# Streamable HTTP mode exposes LINE Desktop read/send tools without MCP authentication\n\n## Summary\n\n`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.\n\nThis 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.\n\n## Affected version\n\nRepository: `dtwang/line-desktop-mcp`\n\nCurrent source checked: `fbed0d2d3048e63f48a356a1267ed8ec5e78f3ae` on `main`, committed 2026-05-14.\n\nPublished npm package checked: `line-desktop-mcp@1.1.1`.\n\n## Source evidence\n\n`README.md` documents Streamable HTTP mode:\n\n```text\nnpx line-desktop-mcp@latest --http-mode --port 3000\n```\n\nThe same README documents MCP endpoints at `/mcp` and explains that this mode is intended for clients such as n8n.\n\n`src/server.js` registers LINE Desktop tools including:\n\n- `get_line_chatroom_history_default`\n- `get_line_chatroom_history_long`\n- `get_line_chatroom_history_short`\n- `send_message_manual`\n- `send_message_auto`\n\nThose tool handlers call into the desktop automation layer: `getChatHistory(...)` and `sendChatMessage(...)`.\n\nIn 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.\n\nThe listener is explicitly network-bound:\n\n```js\napp.listen(port, 0.0.0.0, () => {\n  console.error(`LINE Desktop MCP Server running on Streamable HTTP mode`);\n  console.error(`  Local:   http://127.0.0.1:${port}${endpoint}`);\n  console.error(`  Network: http://0.0.0.0:${port}${endpoint}`);\n});\n```\n\n## Vulnerability chain\n\n1. A user starts the server with `--http-mode --port 3000`.\n2. The server binds on `0.0.0.0:3000`, not only loopback.\n3. A network client reaches `/mcp` and sends the normal MCP initialize request.\n4. The server creates a Streamable HTTP session without authenticating the caller.\n5. The caller can list and invoke LINE Desktop tools.\n6. Tool calls execute through the logged-in LINE Desktop application on the user workstation.\n\n## Impact\n\nAn unauthenticated network client can read LINE chat history through the MCP history tools and can send LINE messages through the send-message tools, including `send_message_auto` when the tool call requests immediate sending. The attacker does not need LINE credentials or a LINE API token; they only need network reachability to the MCP HTTP port.\n\nThe practical impact is disclosure of private LINE conversations and unauthorized messages sent as the logged-in desktop user.\n\n## Suggested fix\n\nRequire authentication before accepting Streamable HTTP MCP sessions or tool calls. For example:\n\n- require a bearer token or local secret when `--http-mode` is used;\n- bind HTTP mode to `127.0.0.1` by default unless the operator explicitly opts into network exposure;\n- refuse to start `0.0.0.0` HTTP mode without authentication;\n- document that `host.docker.internal` / n8n setups must still authenticate to the MCP server.\n\nA defense-in-depth improvement would also keep `send_message_auto` disabled unless explicitly enabled by a server-side flag, because it converts MCP tool access into immediate message sending as the desktop user.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "line-desktop-mcp"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.1.2"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 1.1.1"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/dtwang/line-desktop-mcp/security/advisories/GHSA-4hf8-5mjm-rfgq"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-49357"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/dtwang/line-desktop-mcp/commit/680617894981ea93f8f6ceb51ecde7519754d501"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/dtwang/line-desktop-mcp"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-306", "CWE-862" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-06-26T21:50:49Z",
    "nvd_published_at" : "2026-06-19T14:16:23Z"
  }
}