CVE-2021-29565: Null pointer dereference in `SparseFillEmptyRows`

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2021-05-14 · updated 2026-06-17
Weakness: CWE-476

Description

TensorFlow is an end-to-end open source platform for machine learning. An attacker can trigger a null pointer dereference in the implementation of `tf.raw_ops.SparseFillEmptyRows`. This is because of missing validation(https://github.com/tensorflow/tensorflow/blob/fdc82089d206e281c628a93771336bf87863d5e8/tensorflow/core/kernels/sparse_fill_empty_rows_op.cc#L230-L231) that was covered under a `TODO`. If the `dense_shape` tensor is empty, then `dense_shape_t.vec<>()` would cause a null pointer dereference in the implementation of the op. 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

tensorflow: before 2.1.4; from 2.2.0 before 2.2.3; from 2.3.0 before 2.3.3; from 2.4.0 before 2.4.2 — fixed in 2.1.4, 2.2.3, 2.3.3, 2.4.2

How to fix

Upgrade to a fixed version: tensorflow 2.1.4, 2.2.3, 2.3.3, 2.4.2. Check the vendor advisory for mitigations.

References

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