Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.0, Open WebUI allows admins to restrict which API endpoints an API key can access. When an API key is restricted from /api/v1/messages, requests using the Authorization: Bearer sk-... header are correctly blocked with 403. However, the same key sent via the x-api-key header bypasses the restriction entirely — the request is authenticated, the model is invoked, and a full response is returned. This vulnerability is fixed in 0.9.0.

Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.0, the LDAP authentication endpoint does not validate that the submitted password is non-empty before performing a Simple Bind against the LDAP server. The LdapForm Pydantic model accepts password: str with no minimum length constraint, so an empty string passes validation. The subsequent Connection.bind() call succeeds on vulnerable LDAP servers, and the application issues a full session token for the target user. This vulnerability is fixed in 0.9.0.

Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.0, the channel router does not call filter_allowed_access_grants on either create or update paths. A non-admin user who can create group channels (or who owns a channel) can submit arbitrary access grants — including public wildcard grants — and those grants are stored verbatim, bypassing the admin's permission framework. This vulnerability is fixed in 0.9.0.

Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.0, the AccountPending.svelte component renders the admin-configured "Pending User Overlay Content" using marked.parse() inside {@html} with an incorrect DOMPurify application order. An admin can inject arbitrary JavaScript into the Pending User Overlay Content that executes in the browser context of any pending user who views the overlay page. This vulnerability is fixed in 0.9.0.

Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.0, the /api/generate, /api/embed, /api/embeddings, and /api/show endpoints accept any model name from the user and forward the request to the Ollama backend without checking whether the user is authorized to access that model. These endpoints only require get_verified_user (any authenticated non-pending user) and validate that the model exists in the full unfiltered model list, but never check AccessGrants.has_access(). This vulnerability is fixed in 0.9.0.

Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.5, when setting model permissions so that a group has read access to it, intending for other users to use it, those users also can read the model's system prompt. However users may consider their system prompt confidential, so this is considered a security issue. This vulnerability is fixed in 0.9.5.

Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.0, any authenticated user can permanently delete files owned by other users via DELETE /api/v1/files/{id} when the target file is referenced in any shared chat. The has_access_to_file() authorization gate unconditionally grants access through its shared-chat branch. It checks neither the requesting user's identity nor the type of operation being performed. File UUIDs (which would otherwise be impractical to guess) are disclosed to any user with read access to a knowledge base via GET /api/v1/knowledge/{id}/files. This vulnerability is fixed in 0.9.0.

Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.0, the /responses endpoint in the OpenAI router accepts any authenticated user and forwards requests directly to upstream LLM providers without enforcing per-model access control. While the primary chat completion endpoint (generate_chat_completion) checks model ownership, group membership, and AccessGrants before allowing a request, the /responses proxy only validates that the user has a valid session via get_verified_user. This allows any authenticated user to interact with any model configured on the instance by sending a POST request to /api/openai/responses with an arbitrary model ID. This vulnerability is fixed in 0.9.0.

Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.3, his advisory tracks a regression of the original Excel-preview XSS (CVE-2026-44549). The same root cause — XLSX.utils.sheet_to_html() output rendered via {@html excelHtml} without DOMPurify — was reintroduced sometime after v0.8.0 and is exploitable again This vulnerability is fixed in 0.9.3.

Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.5, a parsing difference between the urlparse and requests libraries led to an SSRF bypass vulnerability. This vulnerability is fixed in 0.9.5.