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Luu, T.J.

GHSA-m837-xvxr-vqwg: Flowise: Hardcoded CORS wildcard on TTS endpoint enables cross-origin credential abuse from any webpage

mediumvulnerability

security

Source: GitHub Advisory DatabaseMay 20, 2026

Summary

Flowise, an AI tool, has a hardcoded setting that allows any webpage on the internet to make requests to its text-to-speech (TTS, a feature that converts written text into spoken audio) endpoint using your stored credentials. This bypasses the server's normal cross-origin request protection (CORS, which controls what websites can access a server's data), letting malicious webpages secretly generate speech on your behalf.

Solution / Mitigation

Remove the hardcoded CORS wildcard headers from the TTS endpoint. Specifically, delete these lines from `packages/server/src/controllers/text-to-speech/index.ts` at line 83: `res.setHeader('Access-Control-Allow-Origin', '*')` and `res.setHeader('Access-Control-Allow-Headers', 'Cache-Control')`. This allows the server's standard CORS middleware to handle access control instead.