CVE-2021-37648

TensorFlow 2.3.4, 2.4.3, 2.5.1 and 2.6.0 include a fix for CVE-2021-37648: In affected versions the code for 'tf.raw_ops.SaveV2' does not properly validate the inputs and an attacker can trigger a null pointer dereference. The implementation (https://github.com/tensorflow/tensorflow/blob/8d72537c6abf5a44103b57b9c2e22c14f5f49698/tensorflow/core/kernels/save_restore_v2_ops.cc) uses 'ValidateInputs' to check that the input arguments are valid. This validation would have caught the illegal state represented by the reproducer above. However, the validation uses 'OP_REQUIRES' which translates to setting the 'Status' object of the current 'OpKernelContext' to an error status, followed by an empty 'return' statement which just terminates the execution of the function it is present in. However, this does not mean that the kernel execution is finalized: instead, execution continues from the nQext line in 'Compute' that follows the call to 'ValidateInputs'. This is equivalent to lacking the validation. The Tensorflow team has patched the issue in GitHub commit 9728c60e136912a12d99ca56e106b7cce7af5986.