Open WebUI — Vulnerability (CVE-2026-45303)
Date: 2026-05
Affected: openwebui/open_webui
Attack vector: xss
Category: vulnerability-disclosure
Severity: High
CVE: CVE-2026-45303
CWE: CWE-79
CVSS: 7.7 (CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:N)

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.


Mitigations:

Architectural layers (MAESTRO):