Vulnerability · Published May 15, 2026 · Assigned by GitHub_M

CVE-2026-45315Open WebUI: Stored XSS via attacker-controlled file extension in /api/v1/audio/transcriptions

High 8.7

In plain English

A high-severity cross-site scripting in open-webui from open-webui. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 8% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)8.7High

Exploit odds (30 days)0.2%top 91.7% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official 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 packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
PyPI	open-webui	0.9.3	GHSA-m8f9-9whg-f4xr
PyPI	open-webui	0.9.3	PYSEC-2026-2748

Affected products (as reported)

Vendor	Product	Versions
open-webui	open-webui	< 0.9.3

Weakness: CWE-79, CWE-434, CWE-646 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N

References

https://github.com/open-webui/open-webui/security/advisories/GHSA-m8f9-9whg-f4xr x_refsource_CONFIRM