Robert Clapp(@RobertClapp):found an endpoint that validated the URL path but completely skipped the host. it handled audio transcription. the check verified that the path string started with the expected prefix, saw a match, and made the downstream fetch. because the host was never pinned, an external server serving that exact path passed every check. anyone with a public token could point the endpoint at their own box and use the server as a proxy to burn transcription credits. the fix: stop taking URLs from the client entirely. client sends an internal storage key, router validates the prefix, server mints the fetch URL from its own storage origin. accepting full URLs from clients usually just means you built an accidental proxy.

2026.08.29 14:49

found an endpoint that validated the URL path but completely skipped the host. it handled audio transcription. the check verified that the path string started with the expected prefix, saw a match, and made the downstream fetch. because the host was never pinned, an external server serving that exact path passed every check. anyone with a public token could point the endpoint at their own box and use the server as a proxy to burn transcription credits. the fix: stop taking URLs from the client entirely. client sends an internal storage key, router validates the prefix, server mints the fetch URL from its own storage origin. accepting full URLs from clients usually just means you built an accidental proxy.