Affected: cline

Cline is an autonomous coding agent as an SDK, IDE extension, or CLI assistant. In versions 2.13.0 and prior, there is a cross-origin WebSocket hijack vulnerability in Cline Kanban servers. At time of publication, there are no publicly available patches.

Affected: npm: cline

## Summary

The `kanban` npm package (used by the `cline` CLI) starts a WebSocket server on `127.0.0.1:3484` with no Origin header validation. Any website a developer visits can silently connect to the kanban server via WebSocket and:

1. Leak sensitive data in real-time: workspace filesystem paths, task titles/descriptions, git branch info, AI agent chat messages 2. Hijack running AI agent terminals by injecting arbitrary prompts into the agent's input, leading to remote code execution 3. Kill running agent tasks by terminating active sessions via the control WebSocket

WebSocket connections are not subject to CORS restrictions. The browser sends them freely to localhost regardless of the page's origin. The kanban server accepts all connections without checking the Origin header.

## Affected Component

- Package: `kanban` on npm (https://www.npmjs.com/package/kanban) - Repository: https://github.com/cline/kanban - Tested version: 0.1.59 - Installed via: `cline` CLI (`cline --kanban` or default `cline` command) - Endpoints: `ws://127.0.0.1:3484/api/runtime/ws`, `ws://127.0.0.1:3484/api/terminal/io`, `ws://127.0.0.1:3484/api/terminal/control`

## Root Cause

Three WebSocket endpoints are exposed without authentication or Origin validation.

### 1. Runtime state stream (no Origin check on upgrade)

```javascript server.on("upgrade", (request, socket, head) => { if (normalizeRequestPath(requestUrl.pathname) !== "/api/runtime/ws") { return; } // No Origin he…