Textream is a free macOS teleprompter app. Prior to version 1.5.1, the `DirectorServer` WebSocket server (`ws://127.0.0.1:<httpPort+1>`) accepts connections from any origin without validating the HTTP `Origin` header during the WebSocket handshake. A malicious web page visited in the same browser session can silently connect to the local WebSocket server and send arbitrary `DirectorCommand` payloads, allowing full remote control of the teleprompter content. Version 1.5.1 fixes the issue.
https://github.com/f/textream/security/advisories/GHSA-wr3v-x247-337w
https://github.com/f/textream/commit/f5ebad82750b9313386c34af8f0ede50c213a8a0