Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.8.11, an internal-only bypass_filter parameter is exposed on the /openai/chat/completions and /ollama/api/chat HTTP endpoints via FastAPI query string binding, allowing any authenticated user to append ?bypass_filter=true and bypass model access control checks to invoke admin-restricted models. This vulnerability is fixed in 0.8.11.

Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.6.5, through the HTML rendering view, scripts can be injected and executed. The frontend provides a function to visualize the HTML content of a current chat. The content is embedded in an iFrame with the allow-scripts allow-forms allow-same-origin sandbox directive. This means that the content is placed in a sandbox but with permission to execute scripts and access the parent’s data (e.g., local storage). As a result, only a few functions are restricted (e.g., displaying an alert box), but in effect, the sandbox attribute is largely nullified. This vulnerability is fixed in 0.6.5.

Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.5.7, a user can modify another user's model even if its visibility is set to Private. By changing the access permissions during editing, unauthorized access can be gained. This vulnerability is fixed in 0.5.7.

Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.6.31, there is a Cross-Site Scripting vulnerability in Open WebUI SVG renderer implementation. This vulnerability is fixed in 0.6.31.

Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.6.19, there's an IDOR in the channels message management system that allows authenticated users to modify or delete any message within channels they have read access to. The vulnerability exists in the message update and delete endpoints, which implement channel-level authorization but completely lack message ownership validation. While the frontend correctly implements ownership checks (showing edit/delete buttons only for message owners or admins), the backend APIs bypass these protections by only validating channel access permissions without verifying that the requesting user owns the target message. This creates a client-side security control bypass where attackers can directly call the APIs to modify other users' messages. This vulnerability is fixed in 0.6.19.

Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13, 11.4.x <= 11.4.3 Fail to validate the response body of proxied images, which allows a remote attacker to enact client-side DoS via an SVG file served from an attacker-controlled origin under a non-SVG Content-Type header (e.g. image/png) embedded in an og:image meta tag or Markdown image link.. Mattermost Advisory ID: MMSA-2026-00630

Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.8.6, there is a vulnerability in chat completion API, which allows attackers to bypass tool restrictions, potentially enabling unauthorized actions or access. In the chat_completion API, the parameters tool_ids and tool_servers are supplied by the user. These parameters are used to create a tools_dict by the middleware. This is then used by get_tool_by_id to retrieve the appropriate tool. However, there is no checks in that ensures the user that uses the API has permission to use the tool, meaning that a user can invoke any server tool by supplying the correct tool_id or tool_servers parameters via the chat completion API. Moreover, the authentication token stored in the server would be used when invoking the tool, so the tool will be invoked with the server privilege. This vulnerability is fixed in 0.8.6.

Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.8.9, when a regular user [non-admin] logs into the application, a http://IP:8080/api/models? web request is initiated by the application and in response, it reveals the system prompt of available models set by admin on models pages in workspace affecting the confidentiality of application. This vulnerability is fixed in 0.8.9.

Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.1.124, the API does not properly validate that the user has an authorized user role of user. By default, when Open WebUI is configured with new sign-ups enabled, the default user role is set to pending. In this configuration, an administrator is required to go into the Admin management panel following a new user registration and reconfigure the user to have a role of either user or admin before that user is able to access the web application. This vulnerability is fixed in 0.1.124.

Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.0, administrative role changes and user deletions do not iterate SESSION_POOL to disconnect affected sessions. As a result, a user whose admin role has been revoked retains admin privileges within their existing Socket.IO session for as long as they keep the connection alive (via automatic heartbeats). The gap is exclusive to the Socket.IO session cache. This vulnerability is fixed in 0.9.0.