fix: get_image_base64_from_file_id

backend/open_webui/routers/channels.py

@@ -934,7 +934,7 @@ async def model_response_handler(request, channel, message, user, db=None):
                         if file.get('type', '') == 'image':
                             images.append(file.get('url', ''))
                         elif file.get('content_type', '').startswith('image/'):
-                            image = await get_image_base64_from_file_id(file.get('id', ''))
+                            image = await get_image_base64_from_file_id(file.get('id', ''), user=user)
                             if image:
                                 images.append(image)
 

backend/open_webui/utils/files.py

@@ -22,6 +22,7 @@ from open_webui.models.chats import Chats
 from open_webui.models.files import Files
 from open_webui.retrieval.web.utils import validate_url
 from open_webui.routers.files import upload_file_handler
+from open_webui.utils.access_control.files import has_access_to_file
 from open_webui.routers.images import (
     get_image_data,
     upload_image,
@@ -50,7 +51,7 @@ _IMAGE_MIME_FALLBACK = {
 }
 
 
-async def get_image_base64_from_url(url: str) -> Optional[str]:
+async def get_image_base64_from_url(url: str, user=None) -> Optional[str]:
     try:
         if url.startswith('http'):
             # Validate URL to prevent SSRF attacks against local/private networks.
@@ -70,25 +71,9 @@ async def get_image_base64_from_url(url: str) -> Optional[str]:
                 content_type = response.headers.get('Content-Type', 'image/png')
                 return f'data:{content_type};base64,{encoded_string}'
         else:
-            file = await Files.get_file_by_id(url)
-
-            if not file:
-                return None
-
-            file_path = await asyncio.to_thread(Storage.get_file, file.path)
-            file_path = Path(file_path)
-
-            if file_path.is_file():
-                with open(file_path, 'rb') as image_file:
-                    encoded_string = base64.b64encode(image_file.read()).decode('utf-8')
-                    content_type = mimetypes.guess_type(file_path.name)[0] or (file.meta or {}).get('content_type')
-                    if not content_type and ENABLE_IMAGE_CONTENT_TYPE_EXTENSION_FALLBACK:
-                        content_type = _IMAGE_MIME_FALLBACK.get(file_path.suffix.lower())
-                    if not content_type:
-                        return None
-                    return f'data:{content_type};base64,{encoded_string}'
-            else:
-                return None
+            # Non-URL string — treat as file_id. Delegate to the canonical
+            # file-ID resolver which enforces ownership/access checks.
+            return await get_image_base64_from_file_id(url, user=user)
 
     except Exception as e:
         return None
@@ -194,11 +179,25 @@ async def get_file_url_from_base64(request, base64_file_string, metadata, user):
     return None
 
 
-async def get_image_base64_from_file_id(id: str) -> Optional[str]:
+async def get_image_base64_from_file_id(id: str, user=None) -> Optional[str]:
     file = await Files.get_file_by_id(id)
     if not file:
         return None
 
+    # Gate file-by-id resolution by ownership to prevent exfiltration.
+    # A caller could place another user's file_id in an image_url field;
+    # without this check the server reads the file from disk, inlines it
+    # base64 into the LLM request, and the content leaks via OCR/describe.
+    # Owner, admin, and explicit read-grant holders are allowed.
+    if user is None:
+        return None
+    if (
+        file.user_id != user.id
+        and user.role != 'admin'
+        and not await has_access_to_file(file.id, 'read', user)
+    ):
+        return None
+
     try:
         file_path = await asyncio.to_thread(Storage.get_file, file.path)
         file_path = Path(file_path)

backend/open_webui/utils/middleware.py

@@ -2096,7 +2096,7 @@ def apply_params_to_form_data(form_data, model):
     return form_data
 
 
-async def convert_url_images_to_base64(form_data):
+async def convert_url_images_to_base64(form_data, user=None):
     messages = form_data.get('messages', [])
 
     for message in messages:
@@ -2117,7 +2117,7 @@ async def convert_url_images_to_base64(form_data):
                 continue
 
             try:
-                base64_data = await get_image_base64_from_url(image_url)
+                base64_data = await get_image_base64_from_url(image_url, user=user)
                 if base64_data:
                     new_content.append(
                         {
@@ -2340,7 +2340,7 @@ async def process_chat_payload(request, form_data, user, metadata, model):
         except Exception:
             pass
 
-    form_data = await convert_url_images_to_base64(form_data)
+    form_data = await convert_url_images_to_base64(form_data, user=user)
 
     event_emitter = await get_event_emitter(metadata)
     event_caller = await get_event_call(metadata)