High-severity WebSocket hijack in Cline's dashboard (CVE-2026-59723)

What changed

The Cline Hub dashboard started by cline dashboard accepted WebSocket connections on its /browser endpoint without checking the Origin header, and with no ROOM_SECRET set (the default for a local bind) any web page the developer visited could connect. An attacker could read session and provider state and add a malicious stdio MCP server; because dashboard sessions auto-approve tools, that could lead to running commands. The advisory lists the cline npm package at 3.0.24 and earlier as affected.

Who it affects

Developers who ran the Cline CLI’s dashboard command on version 3.0.24 or earlier.

What to do

Update the cline npm package, set ROOM_SECRET if you run the dashboard, and check cline_mcp_settings.json for MCP servers you didn’t add.

Source: https://github.com/cline/cline/security/advisories/GHSA-3cj3-hqcr-g934