Stack overflow in `ParseAttrValue` with nested tensors

Impact

The implementation of ParseAttrValue can be tricked into stack overflow due to recursion by giving in a specially crafted input.

Patches

We have patched the issue in GitHub commit e07e1c3d26492c06f078c7e5bf2d138043e199c1.

The fix will be included in TensorFlow 2.5.0. We will also cherrypick this commit on TensorFlow 2.4.2, TensorFlow 2.3.3, TensorFlow 2.2.3 and TensorFlow 2.1.4, as these are also affected and still in supported range.

For more information

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