Missing validation during checkpoint loading

Impact

An attacker can trigger undefined behavior, integer overflows, segfaults and CHECK-fail crashes if they can change saved checkpoints from outside of TensorFlow.

This is because the checkpoints loading infrastructure is missing validation for invalid file formats.

Patches

We have patched the issue in GitHub commits b619c6f865715ca3b15ef1842b5b95edbaa710ad, e8dc63704c88007ee4713076605c90188d66f3d2, 368af875869a204b4ac552b9ddda59f6a46a56ec, and abcced051cb1bd8fb05046ac3b6023a7ebcc4578.

These fixes will be included in TensorFlow 2.7.0. We will also cherrypick these commits on TensorFlow 2.6.1, TensorFlow 2.5.2, and TensorFlow 2.4.4, as these are also affected and still in supported range.

For more information

Please consult our security guide for more information regarding the security model and how to contact us with issues and questions.