GHSA-8gj2-2cvc-6xx7: Flowise: Unauthenticated Credential Abuse via Text-to-Speech Endpoint Allows Unauthorized Use of Private Chatflow TTS Credentials

The /api/v1/text-to-speech/generate endpoint is whitelisted (requires no authentication) and accepts any chatflowId without checking whether the referenced chatflow is public. An unauthenticated attacker who knows a valid chatflow UUID can abuse that chatflow’s TTS credential (OpenAI or ElevenLabs API key) to generate unlimited text-to-speech audio, incurring costs on the chatflow owner’s account.