Vulnerability · Published Jun 19, 2026 · Assigned by GitHub_M
CVE-2026-49357Streamable HTTP mode exposes LINE Desktop read/send tools without MCP authentication
High 8.8
In plain English
A high-severity missing authentication in line-desktop-mcp from dtwang. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 47% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
Line Desktop MCP is a project that, while unaffiliated with the official line-bot-mcp-server, allows users to directly operate the LINE Desktop application on Windows or Mac via MCP. `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. Prior to version 1.1.2, 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. Version 1.1.2 fixes the issue.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| npm | line-desktop-mcp | 1.1.2 | GHSA-4hf8-5mjm-rfgq |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| dtwang | line-desktop-mcp | < 1.1.2 |
Weakness: CWE-306, CWE-862 · Vector: 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