CVE-2026-45315 Details
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.
A stored cross-site scripting vulnerability has been identified in Open WebUI versions prior to 0.9.3. The issue arises in the audio transcription upload endpoint, where the file extension is derived from the user-supplied filename and saved in the cache directory. The cached files are served without a Content-Disposition header, allowing a verified user with the chat.stt permission to upload a polyglot WAV+HTML file. This file can then be used to execute scripts in the Open WebUI origin by tricking another user into opening the file's URL.
Users can update to Open WebUI version 0.9.3 or later, where this vulnerability is fixed. Alternatively, the 'USER_PERMISSIONS_CHAT_STT' setting can be disabled for non-admin users to prevent them from uploading files that could exploit this vulnerability.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed May 19, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://github.com/open-webui/open-webui/security/advisories/GHSA-m8f9-9whg-f4xr | CISA-ADP | ExploitMitigationVendor Advisory |
| https://github.com/open-webui/open-webui/security/advisories/GHSA-m8f9-9whg-f4xr | [email protected] | ExploitMitigationVendor Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-434 | Unrestricted Upload of File with Dangerous Type | [email protected] |
| CWE-646 | Reliance on File Name or Extension of Externally-Supplied File | [email protected] |
| CWE-79 | Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| openwebui open webui | < 0.9.3 |
CPE
Remediation
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Change History
5 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| May 19, 2026 | CVE Modified | CISA-ADP |
| May 18, 2026 | Initial Analysis | [email protected] |
| May 15, 2026 | New CVE Received | [email protected] |