CVE-2026-44563: Open WebUI's Ollama Model Access Control Bypass via /api/generate, /api/embed, /api/embeddings, and /api/show

Four Ollama proxy 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 is in direct contrast with the /ollama/api/chat endpoint (line 1101-1122) which correctly validates model access grants and returns 403 for unauthorized users: