Uninitialized variable access in Tensorflow

Impact

The implementation of AssignOp can result in copying unitialized data to a new tensor. This later results in undefined behavior.

The implementation has a check that the left hand side of the assignment is initialized (to minimize number of allocations), but does not check that the right hand side is also initialized.

Patches

We have patched the issue in GitHub commit ef1d027be116f25e25bb94a60da491c2cf55bd0b.

The fix will be included in TensorFlow 2.8.0. We will also cherrypick this commit on TensorFlow 2.7.1, TensorFlow 2.6.3, and TensorFlow 2.5.3, as these are also affected and still in supported range.

For more information

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