diff --git a/server/main.py b/server/main.py
index 8adc3c74e..89683b3dd 100644
--- a/server/main.py
+++ b/server/main.py
@@ -13,7 +13,7 @@ from slowapi import _rate_limit_exceeded_handler
 from slowapi.errors import RateLimitExceeded
 from sqlalchemy import func, select
 
-from auth import ADMIN_API_KEY, AUTH_DISABLED, JWT_SECRET, require_admin, verify_auth
+from auth import ADMIN_API_KEY, AUTH_DISABLED, JWT_SECRET, _ensure_admin, require_admin, verify_auth
 from errors import (
     UpstreamError,
     install_request_id_logging,
@@ -386,19 +386,27 @@ def _list_all_memories(limit: int = ALL_MEMORIES_LIMIT) -> Dict[str, Any]:
 
 @app.get("/memories", summary="Get memories")
 def get_all_memories(
+    request: Request,
     user_id: Optional[str] = None,
     run_id: Optional[str] = None,
     agent_id: Optional[str] = None,
-    _auth=Depends(verify_auth),
+    user: User | None = Depends(verify_auth),
 ):
-    """Retrieve stored memories. Lists all memories when no identifier is provided."""
+    """Retrieve stored memories. Lists all memories when no identifier is provided.
+
+    Note: the unfiltered listing branch is admin-only — it would otherwise leak
+    every payload in the vector store across tenants once multi-user lands.
+    Filtered queries remain available to any authenticated caller."""
     try:
         if not any([user_id, run_id, agent_id]):
+            _ensure_admin(request, user)
             return _list_all_memories()
         filters = {
             k: v for k, v in {"user_id": user_id, "run_id": run_id, "agent_id": agent_id}.items() if v is not None
         }
         return get_memory_instance().get_all(filters=filters)
+    except HTTPException:
+        raise
     except Exception:
         raise upstream_error()
 
diff --git a/server/tests/test_admin_gating.py b/server/tests/test_admin_gating.py
index 0d30a68b2..e236b851c 100644
--- a/server/tests/test_admin_gating.py
+++ b/server/tests/test_admin_gating.py
@@ -185,3 +185,38 @@ def test_get_requests_member_forbidden(client, auth_member_header):
 def test_get_requests_no_auth_unauthorized(client):
     response = client.get("/requests")
     assert response.status_code == 401
+
+
+# --- GET /memories (no filter branch only) ---
+
+
+def test_get_memories_no_filter_admin_jwt(client, auth_admin_header):
+    response = client.get("/memories", headers=auth_admin_header)
+    assert response.status_code == 200
+
+
+def test_get_memories_no_filter_admin_api_key(client, admin_api_key_env):
+    response = client.get("/memories", headers=admin_api_key_env)
+    assert response.status_code == 200
+
+
+def test_get_memories_no_filter_auth_disabled(client, auth_disabled_env):
+    response = client.get("/memories")
+    assert response.status_code == 200
+
+
+def test_get_memories_no_filter_member_forbidden(client, auth_member_header):
+    """The info-disclosure branch (_list_all_memories) is admin-only."""
+    response = client.get("/memories", headers=auth_member_header)
+    assert response.status_code == 403
+
+
+def test_get_memories_filtered_member_succeeds(client, auth_member_header):
+    """Filtered queries are unchanged — member can still call them."""
+    response = client.get("/memories?user_id=alice", headers=auth_member_header)
+    assert response.status_code == 200
+
+
+def test_get_memories_no_auth_unauthorized(client):
+    response = client.get("/memories")
+    assert response.status_code == 401