CVE-2021-29512

Tensorflow-gpu versions 2.1.4, 2.2.3, 2.3.3, 2.4.2 and 2.5.0 include a fix for CVE-2021-29512: If the 'splits' argument of 'RaggedBincount' does not specify a valid 'SparseTensor' (https://www.tensorflow.org/api_docs/python/tf/sparse/SparseTensor), then an attacker can trigger a heap buffer overflow. This will cause a read from outside the bounds of the 'splits' tensor buffer in the implementation of the 'RaggedBincount' op (https://github.com/tensorflow/tensorflow/blob/8b677d79167799f71c42fd3fa074476e0295413a/tensorflow/core/kernels/bincount_op.cc#L430-L433). Before the 'for' loop, 'batch_idx' is set to 0. The user controls the 'splits' array, making it contain only one element, 0. Thus, the code in the 'while' loop would increment 'batch_idx' and then try to read 'splits(1)', which is outside of bounds.