CVE-2026-54011 Details
Description
Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.6,Open WebUI renders Mermaid blocks from Markdown files in the file preview panel and inserts the generated SVG into the DOM using innerHTML. Because Mermaid is configured with securityLevel: 'loose', attacker-controlled Mermaid content can be rendered unsafely in this flow. A working payload was validated through the Markdown preview path, resulting in JavaScript execution in the victim’s browser under the application origin. This vulnerability is fixed in 0.9.6.
A stored cross-site scripting vulnerability has been identified in Open WebUI versions prior to 0.9.6. The issue arises because the application renders Mermaid blocks from Markdown files in the file preview panel, injecting the generated SVG into the DOM using innerHTML. With Mermaid's security level set to 'loose', this allows attacker-controlled content to be rendered unsafely, leading to JavaScript execution in the victim's browser under the application origin. The vulnerability can be exploited by uploading a malicious Markdown file containing a crafted Mermaid diagram that executes JavaScript when the file is previewed.
Users are advised to update to Open WebUI version 0.9.6 or later, and to configure Mermaid to use 'strict' mode instead of 'loose'.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Jun 23, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://github.com/open-webui/open-webui/security/advisories/GHSA-v8qj-hxv7-mgvv | CISA-ADP | ExploitMitigationVendor Advisory |
| https://github.com/open-webui/open-webui/security/advisories/GHSA-v8qj-hxv7-mgvv | [email protected] | ExploitMitigationVendor Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-79 | Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| openwebui open webui | < 0.9.6 |
CPE
Remediation
| |
Change History
3 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 25, 2026 | Initial Analysis | [email protected] |
| Jun 23, 2026 | New CVE Received | [email protected] |
| Jun 23, 2026 | CVE Modified | CISA-ADP |