GHSA-3cj3-hqcr-g934: Cline: Cross-Origin WebSocket Hijacking in Cline Hub Dashboard (`/browser` endpoint)

Summary

The Cline Hub dashboard server (`@cline/cline-hub`), launched with the `cline dashboard` CLI command, accepts WebSocket connections on `/browser` without validating the HTTP `Origin` header. When `ROOM_SECRET` is unset, which is the default for `127.0.0.1` binds, `isAuthorizedBrowserRequest()` returns `true`, so any website a developer visits can open a cross-origin WebSocket to `ws://127.0.0.1:8787/browser`. Dashboard sessions default to `autoApprove: true` for all tools, and the source reports that an injected `upsert_mcp_server` frame wrote a malicious `stdio` MCP server entry into the victim's Cline settings file.

Mitigation

The source does not state a fix yet. Check the original advisory for updates.

Topics

• Model Context Protocol

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