diff --git a/onnxruntime/core/graph/graph.cc b/onnxruntime/core/graph/graph.cc
index 15e7fad0d4a1a..5fd2f60a8dbfe 100644
--- a/onnxruntime/core/graph/graph.cc
+++ b/onnxruntime/core/graph/graph.cc
@@ -3730,8 +3730,24 @@ Status Graph::ConvertInitializersIntoOrtValues() {
     auto& graph_proto = *graph.graph_proto_;
     for (int i = 0, lim = graph_proto.initializer_size(); i < lim; ++i) {
       auto& tensor_proto = *graph_proto.mutable_initializer(i);
+
       if (utils::HasExternalData(tensor_proto)) {
-        continue;  // ignore data on disk, that will be loaded either by EP or at session_state finalize
+        if (utils::HasExternalDataInMemory(tensor_proto)) {
+          // This can happen when the model is created with ModelEditor.
+          // We want to guard against malicious models with arbitrary in-memory references.
+          if (OrtValue v; GetOrtValueInitializer(tensor_proto.name(), v)) {
+            ORT_RETURN_IF_NOT(graph_utils::CheckInMemoryDataMatch(tensor_proto, v.Get<Tensor>()),
+                              "In-memory data mismatch for initializer: ", tensor_proto.name(),
+                              " this is an invalid model");
+          } else {
+            return ORT_MAKE_STATUS(ONNXRUNTIME, FAIL,
+                                   "The model contains initializers with arbitrary in-memory references.",
+                                   "This is an invalid model.");
+          }
+        }
+        // ignore data on disk, that will be loaded either by EP or at session_state finalize
+        // ignore valid in-memory references
+        continue;
       }
 
       size_t size_in_bytes = 0;
@@ -3830,6 +3846,10 @@ Status Graph::AddInitializedOrtValue(const ONNX_NAMESPACE::TensorProto& tensor_p
     const auto proto_shape = utils::GetTensorShapeFromTensorProto(tensor_proto);
     ORT_RETURN_IF_NOT(proto_shape == tensor.Shape(), "Shape mismatch with ortvalue_initializer");
 
+    const bool data_ptr_match = graph_utils::CheckInMemoryDataMatch(tensor_proto, tensor);
+    ORT_RETURN_IF_NOT(data_ptr_match,
+                      "In-memory data pointer mismatch between tensor proto and ortvalue_initializer");
+
     ortvalue_initializers_.insert_or_assign(tensor_proto.name(), ortvalue_initializer);
   } else {
     ORT_ENFORCE(ortvalue_initializers_.count(tensor_proto.name()) == 0,
diff --git a/onnxruntime/test/shared_lib/test_inference.cc b/onnxruntime/test/shared_lib/test_inference.cc
index a39b9c89e5898..7230a22246318 100644
--- a/onnxruntime/test/shared_lib/test_inference.cc
+++ b/onnxruntime/test/shared_lib/test_inference.cc
@@ -4761,3 +4761,36 @@ TEST(CApiTest, custom_cast) {
                                inputs, "output", expected_dims_y, expected_values_y, 0,
                                custom_op_domain, nullptr);
 }
+
+TEST(CApiTest, ModelWithMaliciousExternalDataShouldFailToLoad) {
+  // Attempt to create an ORT session with the malicious model
+  // This should fail due to the invalid external data reference
+  constexpr const ORTCHAR_T* model_path = TSTR("testdata/test_evil_weights.onnx");
+
+  Ort::Env env(ORT_LOGGING_LEVEL_WARNING, "test");
+  Ort::SessionOptions session_options;
+
+  bool exception_thrown = false;
+  std::string exception_message;
+
+  try {
+    // This should throw an exception due to malicious external data
+    Ort::Session session(env, model_path, session_options);
+  } catch (const Ort::Exception& e) {
+    exception_thrown = true;
+    exception_message = e.what();
+  } catch (const std::exception& e) {
+    exception_thrown = true;
+    exception_message = e.what();
+  }
+
+  // Verify that loading the model failed
+  EXPECT_TRUE(exception_thrown) << "Expected model loading to fail due to malicious external data";
+
+  // Verify that the exception message indicates security or external data issues
+  EXPECT_TRUE(exception_message.find("in-memory") != std::string::npos ||
+              exception_message.find("references") != std::string::npos ||
+              exception_message.find("invalid") != std::string::npos ||
+              exception_message.find("model") != std::string::npos)
+      << "Exception message should indicate external data or security issue. Got: " << exception_message;
+}
diff --git a/onnxruntime/test/testdata/test_evil_weights.onnx b/onnxruntime/test/testdata/test_evil_weights.onnx
new file mode 100644
index 0000000000000..7f538fc1df1aa
Binary files /dev/null and b/onnxruntime/test/testdata/test_evil_weights.onnx differ
diff --git a/onnxruntime/test/testdata/test_evil_weights.py b/onnxruntime/test/testdata/test_evil_weights.py
new file mode 100644
index 0000000000000..61be312474612
--- /dev/null
+++ b/onnxruntime/test/testdata/test_evil_weights.py
@@ -0,0 +1,50 @@
+import onnx
+
+
+def create_exp_model():
+    inputs = []
+    nodes = []
+    tensors = []
+    outputs = []
+
+    input_ = onnx.helper.make_tensor_value_info("input", onnx.TensorProto.INT64, [None, None])
+    inputs.append(input_)
+
+    evil_tensor = onnx.helper.make_tensor(
+        name="evil_weights",
+        data_type=onnx.TensorProto.INT64,
+        # dims=[100, 100],
+        dims=[10],
+        vals=[],
+    )
+    tensors.append(evil_tensor)
+    evil_tensor.data_location = onnx.TensorProto.EXTERNAL
+    entry1 = evil_tensor.external_data.add()
+    entry1.key = "location"
+    entry1.value = "*/_ORT_MEM_ADDR_/*"
+    entry2 = evil_tensor.external_data.add()
+    entry2.key = "offset"
+    entry2.value = "4194304"
+    entry2.value = "12230656"
+    entry3 = evil_tensor.external_data.add()
+    entry3.key = "length"
+    entry3.value = "80"
+
+    tensors.append(onnx.helper.make_tensor(name="0x1", data_type=onnx.TensorProto.INT64, dims=[1], vals=[0x1]))
+    nodes.append(onnx.helper.make_node(op_type="Add", inputs=["evil_weights", "0x1"], outputs=["output"]))
+
+    outputs.append(onnx.helper.make_tensor_value_info("output", onnx.TensorProto.INT64, []))
+
+    graph = onnx.helper.make_graph(nodes, "test", inputs, outputs, tensors)
+    model = onnx.helper.make_model(
+        graph,
+        opset_imports=[onnx.helper.make_opsetid("", 18), onnx.helper.make_opsetid("ai.onnx.ml", 3)],
+        ir_version=11,
+    )
+
+    return model
+
+
+if __name__ == "__main__":
+    model = create_exp_model()
+    onnx.save(model, "test_evil_weights.onnx")