CVE-2026-70486: XSS (CVSS 8.2)

Description

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.

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CVSS v3.1 Score

8.2

HIGH

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

Weakness Type (CWE)

CWE-79 Cross-site Scripting (XSS)

CWE-1021 CWE-1021

References

Other References

https://github.com/open-webui/open-webui/commit/65a5fad7b97db99d490d81f4e0860282c3a4543c https://github.com/open-webui/open-webui/pull/26907 https://github.com/open-webui/open-webui/releases/tag/v0.11.0 https://github.com/open-webui/open-webui/security/advisories/GHSA-3xpf-xq7r-v8c5

Frequently Asked Questions

What is 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. It has a CVSS v3.1 base score of 8.2 (HIGH).

How severe is CVE-2026-70486? +

CVE-2026-70486 has a CVSS v3.1 score of 8.2 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.

How do I check if I'm vulnerable to CVE-2026-70486? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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