Flowise: Hardcoded CORS wildcard on TTS endpoint enables cross-origin credential abuse from any webpage

Summary

The TTS generation endpoint sets Access-Control-Allow-Origin: * as a hardcoded response header, independent of the server's CORS configuration. This enables any webpage to make cross-origin requests to generate speech using stored credentials.

Root Cause

// packages/server/src/controllers/text-to-speech/index.ts:83
res.setHeader('Access-Control-Allow-Origin', '*')
res.setHeader('Access-Control-Allow-Headers', 'Cache-Control')

Impact

• Cross-origin credential abuse — any webpage can trigger TTS using stored credentials
• Bypasses the server's CORS policy (getCorsOptions()) which is otherwise restrictive by default
• Combined with Finding 3 (TTS credential abuse), enables drive-by credential abuse via malicious webpages

Suggested Fix

Remove the hardcoded CORS wildcard and let the server's CORS middleware handle the headers:

// Remove these lines:
// res.setHeader('Access-Control-Allow-Origin', '*')
// res.setHeader('Access-Control-Allow-Headers', 'Cache-Control')

References

• packages/server/src/controllers/text-to-speech/index.ts line 83