Cross-site scripting in Open WebUI - #VU135953
Published: June 30, 2026
Vulnerability identifier: #VU135953
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:U/U:Clear
CVE-ID: N/A
CWE-ID: CWE-79
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Open WebUI
Affected software:
Open WebUI
Open WebUI
Detailed vulnerability description
The vulnerability allows a remote user to execute arbitrary code on the server.
The vulnerability exists due to cross-site scripting in the Pyodide code execution feature when processing Python code stored in a shared chat and executed in a same-origin worker. A remote user can store a crafted payload in a shared chat and induce the victim to click Run to execute arbitrary code on the server.
User interaction is required, and exploitation for server-side code execution depends on the victim having admin privileges or the workspace.functions or workspace.tools permissions. Open WebUI must be configured to use Pyodide.
Remediation
Install security update from vendor's website.