CVE-2026-45303 HIGH

CVE-2026-45303: Open WebUI: Stored XSS via the HTML renedering view

Vendor Open-Webui
Product open-webui
Weakness CWE-79 · XSS
Published May 15, 2026
Last update May 19, 2026

CVSS base score

7.7/10
Attack vector Network
Attack complexity High
Privileges required Low
User interaction Required
Confidentiality High
Integrity High

CVSS vector

CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:N

What the vulnerability does

01Description

Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.6.5, through the HTML rendering view, scripts can be injected and executed. The frontend provides a function to visualize the HTML content of a current chat. The content is embedded in an iFrame with the allow-scripts allow-forms allow-same-origin sandbox directive. This means that the content is placed in a sandbox but with permission to execute scripts and access the parent’s data (e.g., local storage). As a result, only a few functions are restricted (e.g., displaying an alert box), but in effect, the sandbox attribute is largely nullified. This vulnerability is fixed in 0.6.5.

Key dates

02Disclosure timeline

May 15, 2026 CVE published
May 19, 2026 Record updated