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.
History

Fri, 15 May 2026 23:45:00 +0000

Type Values Removed Values Added
First Time appeared Open-webui
Open-webui open-webui
Vendors & Products Open-webui
Open-webui open-webui

Fri, 15 May 2026 22:00:00 +0000

Type Values Removed Values Added
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.
Title Open WebUI: Stored XSS via attacker-controlled file extension in /api/v1/audio/transcriptions
Weaknesses CWE-434
CWE-646
CWE-79
References
Metrics cvssV3_1

{'score': 8.7, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-05-15T21:26:54.790Z

Reserved: 2026-05-11T20:50:30.538Z

Link: CVE-2026-45315

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-05-15T22:16:54.250

Modified: 2026-05-15T22:16:54.250

Link: CVE-2026-45315

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-05-16T00:00:12Z