CVE-2021-37639

TensorFlow 2.3.4, 2.4.3, 2.5.1 and 2.6.0 include a fix for CVE-2021-37639: When restoring tensors via raw APIs, if the tensor name is not provided, TensorFlow can be tricked into dereferencing a null pointer. Alternatively, attackers can read memory outside the bounds of heap allocated data by providing some tensor names but not enough for a successful restoration. The implementation (https://github.com/tensorflow/tensorflow/blob/47a06f40411a69c99f381495f490536972152ac0/tensorflow/core/kernels/save_restore_tensor.cc#L158-L159) retrieves the tensor list corresponding to the 'tensor_name' user controlled input and immediately retrieves the tensor at the restoration index (controlled via 'preferred_shard' argument). This occurs without validating that the provided list has enough values. If the list is empty this results in dereferencing a null pointer (undefined behavior). If, however, the list has some elements and if the restoration index is outside the bounds, this results in heap OOB read. The Tensorflow team has patched the issue in GitHub commit 9e82dce6e6bd1f36a57e08fa85af213e2b2f2622.