Description
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.
Affected products
openwebui: open webui
References2
- github.com/open-webui/open-webui/security/advisories/GHSA-m8f9-… ExploitMitigationVendor Advisory
- github.com/open-webui/open-webui/security/advisories/GHSA-m8f9-… ExploitMitigationVendor Advisory
Metrics
- CVSS 3.1
-
8.7
HIGH
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N - EPSS — exploit probability
- 0% percentile: 8 · as of 14 November 2026
- CWE
- CWE-79CWE-434CWE-646
Could this be exploited in your environment?
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