TensorFlow is an open source platform for machine learning. Prior to versions 2.9.0, 2.8.1, 2.7.2, and 2.6.4, the implementation of "tf.raw_ops.UnsortedSegmentJoin" does not fully validate the input arguments. This results in a "CHECK"-failure which can be used to trigger a denial of service attack. The code assumes "num_segments" is a positive scalar but there is no validation. Since this value is used to allocate the output tensor, a negative value would result in a "CHECK"-failure (assertion failure), as per TFSA-2021-198. Versions 2.9.0, 2.8.1, 2.7.2, and 2.6.4 contain a patch for this issue.