CVE-2020-15190: In Tensorflow before versions 1.15.4, 2.0.3, 2.1.2, 2.2.1 and 2.3.1, the `tf.raw_ops.Switch` operation takes as input a

TensorFlow versions before 1.15.4, 2.0.3, 2.1.2, 2.2.1, and 2.3.1 have a bug in the `tf.raw_ops.Switch` operation where it tries to access a null pointer (a reference to nothing), causing the program to crash. The problem occurs because the operation outputs two tensors (data structures in machine learning frameworks) but only one is actually created, leaving the other as an undefined reference that shouldn't be accessed.