CVE-2026-45315

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

HIGH
8.7
CVSS Score
Published: May 15, 2026 at 09:26 PM UTC
Updated: June 17, 2026 at 10:51 AM UTC
1 product affected across 1 vendorOpen Webui

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Severity
HIGH8.7
Exploit prediction
EPSS 0.2%
SSVC
PoC

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

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 0.9.3
Affected range stops below 0.9.3, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (1)

x_refsource_CONFIRMExploitMitigationVendor Advisory
Source: cverecord
https://github.com/open-webui/open-webui/security/advisories/GHSA-m8f9-9whg-f4xr

SSVC — Action Prioritization

SSVCPoCNot automatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

8.7HIGHGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
LOW
User Interaction
REQUIRED
Scope
CHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
NONE
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-79CWE-434CWE-646

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