XSS in Open-Webui
CVE-2026-70486
Open WebUI is an extensible, feature-rich, and user-friendly self-hosted AI platform. From 0.9.0 until 0.11.0, the terminal file-preview serveUrl iframe branch always granted allow-same-origin together with allow-scripts for HTML files served from the application origin. Any authenticated user with access to a configured terminal server could cause script in a previewed file to run in the Open WebUI origin, read the victim's session token from localStorage, and take over the account, with possible server-side code execution if the victim was an admin or held workspace.functions. This issue is fixed in 0.11.0.
Vulnerability class: XSS (Cross-Site Scripting)
EPSS: 0.004 (31.3th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 8.2 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:N.
Affected products
- Open-webui — versions >= 0.9.0, < 0.11.0
- Openwebui Open_webui
Weakness classification (CWE)
References
- security-advisories@github.com (Patch, x_refsource_MISC)
- security-advisories@github.com (Patch, x_refsource_MISC, Vendor Advisory)
- security-advisories@github.com (x_refsource_MISC, Release Notes)
- security-advisories@github.com (x_refsource_CONFIRM, Exploit, Patch, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-70486?
- CVE-2026-70486 is a high-severity vulnerability in Open-Webui, classified under Cross-site Scripting. CVSS score: 8.2/10. Published 2026-08-04.
- How severe is CVE-2026-70486?
- High severity. CVSS v3 base score is 8.2 out of 10.