Division by zero in TFLite
### Impact
The implementation of fully connected layers in TFLite is vulnerable to a division by zero error
https://github.com/tensorflow/tensorflow/blob/460e000de3a83278fb00b61a16d161b1964f15f4/tensorflow/lite/kernels/fully_connected.cc#L226:
```cc
const int batch_size = input_size / filter->dims->data[1];
```
An attacker can craft a model such that `filter->dims->data[1]` is 0.
### Patches
We have patched the issue in GitHub commit 718721986aa137691ee23f03638867151f74935f
https://github.com/tensorflow/tensorflow/commit/718721986aa137691ee23f03638867151f74935f.
The fix will be included in TensorFlow 2.6.0. We will also cherrypick this commit on TensorFlow 2.5.1, TensorFlow 2.4.3, and TensorFlow 2.3.4, as these are also affected and still in supported range.
### 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 members of the Aivul Team from Qihoo 360. Concurrently, it has also been reported by Yakun Zhang of Baidu Security.