Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.3, the audio transcription upload endpoint takes the file extension from the user-supplied filename and saves the file under CACHE_DIR/audio/transcriptions/.. The /cache/{path} route serves these files via FileResponse, which sets Content-Type from the on-disk extension and emits no Content-Disposition. A verified user with the default-on chat.stt permission can upload a polyglot WAV+HTML file named pwn.html and trick any other user into opening the resulting URL — the response comes back as text/html and any embedded <script> runs in the Open WebUI origin. This vulnerability is fixed in 0.9.3.
CVSS Details
- CVSS 3.1 Base Score: 8.7
- CVSS 3.1 Vector: (CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N)
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