diff --git a/dev/test_router_coordination.py b/dev/test_router_coordination.py
index 163dec2..8914e95 100644
--- a/dev/test_router_coordination.py
+++ b/dev/test_router_coordination.py
@@ -3,6 +3,7 @@ import json
 import os
 import sys
 import threading
+import tempfile
 import unittest
 from pathlib import Path
 from unittest.mock import patch
@@ -25,6 +26,14 @@ class CoordinationTests(unittest.TestCase):
         with self.assertRaisesRegex(RuntimeError, 'rewritten_prompt'):
             router._parse_prompt_enhancer_result('{"wh_ratio":"1:1"}')
 
+    def test_image_data_url_resolves_volume_relative_reference(self):
+        with tempfile.TemporaryDirectory() as directory, \
+             patch.object(router, 'IMAGE_DIR', directory):
+            path = Path(directory) / '.edit-reference.ref'
+            path.write_bytes(b'\x89PNG\r\n\x1a\ncontent')
+            result = router._image_data_url(path.name)
+        self.assertTrue(result.startswith('data:image/png;base64,'))
+
     def test_mode_uses_one_consistent_controller_snapshot(self):
         with patch.object(router, 'PROFILE_CONTROL_URL', 'http://controller'), \
              patch.object(router, '_profile_controller_request', return_value={
diff --git a/router/ai_profile_router.py b/router/ai_profile_router.py
index 61710aa..4ba25a3 100755
--- a/router/ai_profile_router.py
+++ b/router/ai_profile_router.py
@@ -1410,7 +1410,12 @@ def _restore_qwen(profile: str) -> None:
 
 def _image_data_url(path: str) -> str:
     """Read one already validated local reference image as a data URL."""
-    with open(path, "rb") as handle:
+    image_root = os.path.abspath(IMAGE_DIR)
+    resolved = (os.path.abspath(path) if os.path.isabs(path)
+                else os.path.abspath(os.path.join(image_root, path)))
+    if os.path.commonpath((image_root, resolved)) != image_root:
+        raise RuntimeError("Referenzbild liegt außerhalb des Bildverzeichnisses")
+    with open(resolved, "rb") as handle:
         data = handle.read()
     if data.startswith(b"\x89PNG\r\n\x1a\n"):
         mime = "image/png"