Process Compose DNS rebinding vulnerability in MCP SSE

A DNS rebinding vulnerability in Process Compose's MCP SSE transport allows malicious websites to control local process-compose tools without authentication. The vulnerability exists because the MCP SSE listener lacks Host validation, Origin validation, or authentication checks before dispatching requests to control tools.

Disclosed 18 September 2026 · Record updated 18 September 2026

Impact

Malicious websites can use DNS rebinding to control a developer's local process-compose MCP tools, including starting, stopping, restarting, scaling processes, and reading/searching logs.

Our coverage

A spider web stretches from a browser window to silenced factory machines in a locked room, threads vibrating as invisible puppeteer hands pull them taut.

Vulnerabilities

DNS rebinding flaw exposes local Process Compose MCP tools

An advisory published on 18 September 2026 says a malicious web page can drive a developer's process-compose MCP listener with no authentication.

18 Sept 2026

Sources

github.comhttps://github.com/advisories/GHSA-5gm3-9crp-6g3v