Ollama Model Access Control Bypass via /api/generate, /api/embed, /api/embeddings, and /api/show
Affected Component
Ollama proxy endpoints missing model access control:
backend/open_webui/routers/ollama.py (lines 955-995, generate_completion)backend/open_webui/routers/ollama.py (lines 835-881, embed)backend/open_webui/routers/ollama.py (lines 891-937, embeddings)backend/open_webui/routers/ollama.py (lines 791-820, show_model_info)
Affected Versions
Current main branch (commit 6fdd19bf1) and likely all versions with Ollama model access control support.
Description
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:
# /api/chat (line 1101-1122) — CORRECTLY checks access
if not bypass_filter and user.role == 'user':
user_group_ids = {group.id for group in Groups.get_groups_by_member_id(user.id)}
if not (
user.id == model_info.user_id
or AccessGrants.has_access(
user_id=user.id, resource_type='model',
resource_id=model_info.id, permission='read',
user_group_ids=user_group_ids,
)
):
raise HTTPException(status_code=403, detail='Model not found')
# /api/generate (line 955-995) — NO access check at all
# /api/embed (line 835-881) — NO access check at all
# /api/embeddings (line 891-937) — NO access check at all
# /api/show (line 791-820) — NO access check at all
CVSS 3.1 Breakdown
| Metric | Value | Rationale |
|---|
| Attack Vector | Network (N) | Exploited remotely via API calls |
| Attack Complexity | Low (L) | Single API call with a known model name |
| Privileges Required | Low (L) | Requires any authenticated user account |