TensorFlow has Null Pointer Error in TensorArrayConcatV2

Impact

When ctx->step_containter() is a null ptr, the Lookup function will be executed with a null pointer.

```python

import tensorflow as tf

tf.raw_ops.TensorArrayConcatV2(handle=['a', 'b'], flow_in = 0.1, dtype=tf.int32, element_shape_except0=1)

`

Patches

We have patched the issue in GitHub commit [239139d2ae6a81ae9ba499ad78b56d9b2931538a](https://github.com/tensorflow/tensorflow/commit/239139d2ae6a81ae9ba499ad78b56d9b2931538a).

The fix will be included in TensorFlow 2.12.0. We will also cherrypick this commit on TensorFlow 2.11.1

For more information

Please consult [our security guide](https://github.com/tensorflow/tensorflow/blob/master/SECURITY.md) for more information regarding the security model and how to contact us with issues and questions.

Attribution

This vulnerability has been reported by Yu Tian