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

Summary 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. Details The TTS generateTextToSpeech controller at packages/server/src/controllers/text-to-speech/index.ts:10-171 is whitelisted at packages/server/src/utils/constants.ts:41: '/api/v1/text-to-speech/generate', When a chatflowId is provided and the user is not authenticated (no req.user), the controller falls back to fetching the chatflow without workspace scoping: // packages/server/src/controllers/text-to-speech/index.ts:36-42 if (workspaceId) { chatflow = await chatflowsService.getChatflowById(chatflowId, workspaceId) } else { // Fallback: get workspaceId from chatflow when req.user.activeWorkspaceId is not set chatflow = await chatflowsService.getChatflowById(chatflowId) // NO isPublic check workspaceId = chatflow.workspaceId } The getChatflowById function at packages/server/src/services/chatflows/index.ts:247-272 fetches any chatflow by ID when workspaceId is not provided: const dbResponse = await appServer.AppDataSource.getRepository(ChatFlow).findOne({ where: { id: chatflowId, ...(workspaceId ? { workspaceId } : {}) // No workspace filter when workspaceId is undefined } }) The controller then extracts the TTS provider configuration from the chatflow: // packages/server/src/controllers/text-to-speech/index.ts:51-66 const ttsConfig = JSON.parse(chatflow.textToSpeech) const activeProviderKey = Object.keys(ttsConfig).find(key => ttsConfig[key].status === true) const providerConfig = ttsConfig[activeProviderKey] provider = activeProviderKey credentialId = providerConfig.credentialId // Extracted from private chatflow This credentialId is then used to de