CVE-2021-29552: Google Tensorflow

Medium severity, CVSS 5.5. EPSS: 0.2% chance of exploitation in the next 30 days.

TensorFlow is an end-to-end open source platform for machine learning. An attacker can cause a denial of service by controlling the values of `num_segments` tensor argument for `UnsortedSegmentJoin`. This is because the implementation(https://github.com/tensorflow/tensorflow/blob/a2a607db15c7cd01d754d37e5448d72a13491bdb/tensorflow/core/kernels/unsorted_segment_join_op.cc#L92-L93) assumes that the `num_segments` tensor is a valid scalar. Since the tensor is empty the `CHECK` involved in `.scalar<T>()()` that checks that the number of elements is exactly 1 will be invalidated and this would result in process termination. The fix will be included in TensorFlow 2.5.0. We will also cherrypick this commit on TensorFlow 2.4.2, TensorFlow 2.3.3, TensorFlow 2.2.3 and TensorFlow 2.1.4, as these are also affected and still in supported range.

Affected products

• Google Tensorflow: before 2.1.4 (fixed in 2.1.4); from 2.2.0, before 2.2.3 (fixed in 2.2.3); from 2.3.0, before 2.3.3 (fixed in 2.3.3); from 2.4.0, before 2.4.2 (fixed in 2.4.2)

Published 2021-05-14. Last modified 2026-06-17.