Cline Hub Dashboard WebSocket Cross-Origin Hijacking

The Cline Hub dashboard accepts WebSocket connections without validating the Origin header when ROOM_SECRET is not set (the default for local binds), allowing attackers to inject malicious commands and achieve arbitrary code execution through cross-origin WebSocket hijacking.

Disclosed 24 September 2026 · Record updated 1 October 2026

Impact

Attackers can read workspace state, modify MCP and provider settings, and trigger arbitrary command execution on affected systems with auto-approve enabled.

Our coverage

A spider web of glowing threads connects a browser window to an open workshop door, where invisible hands manipulate tools and machines inside an unguarded room.

Vulnerabilities

Cline dashboard flaw lets any website run code on developer machines

A cross-origin WebSocket bug in Cline Hub allows malicious web pages to inject commands and settings on default local installs, disclosed on 24 September 2026.

24 Sept 2026

Sources

github.comhttps://github.com/advisories/GHSA-3cj3-hqcr-g934