CVE-2026-45303: Openwebui Open Webui

High severity, CVSS 7.7. EPSS: 0.3% chance of exploitation in the next 30 days.

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.

Affected products

• Openwebui Open Webui: before 0.6.5 (fixed in 0.6.5)

Published 2026-05-15. Last modified 2026-06-17.