Open WebUI before version 0.11.4 contains a stored cross‑site scripting flaw where markdown link URLs are rendered into anchor hrefs without validating their scheme. Authenticated users can embed javascript: links in shared chats; when a victim clicks such a link the script runs in the victim’s browser and can read the JWT stored in local storage, including that of administrators. This allows identity theft and full impersonation of privileged accounts.

The vulnerability affects Open WebUI, specifically all releases prior to version 0.11.4 as identified by the open-webui:open-webui product according to the CNA. No other vendors or products are listed, and affected versions are those before 0.11.4.

The CVSS score of 7.2 classifies the issue as high severity. EPSS information is not available, and the vulnerability is not listed in CISA’s KEV catalog. The likely attack vector requires an attacker to log in to the platform, embed a malicious javascript: link within a shared chat, and a separate victim to click that link. Because the attacker can be any authenticated user or a compromised account, there is a real risk of widespread exploitation. Prompt remediation is therefore warranted.