AI and data stack advisories

Severe, 6 weeks1498Projects326

1498 severe, 6 weeks · 326 projects

TensorFlowGHSA-59q2-x2qc-4c97

Heap OOB access in unicode ops

TensorFlow

CVE-2021-29559 · Published May 21, 2021 · updated Jul 8, 2026

Low2.5
Fix: upgrade to 2.1.4 or later (4 fixed versions below)
GitHub advisory

Impact

An attacker can access data outside of bounds of heap allocated array in tf.raw_ops.UnicodeEncode:

```python

import tensorflow as tf

input_values = tf.constant([58], shape=[1], dtype=tf.int32)

input_splits = tf.constant([[81, 101, 0]], shape=[3], dtype=tf.int32)

output_encoding = "UTF-8"

tf.raw_ops.UnicodeEncode(

input_values=input_values, input_splits=input_splits,

output_encoding=output_encoding)

`

This is because the [implementation](https://github.com/tensorflow/tensorflow/blob/472c1f12ad9063405737679d4f6bd43094e1d36d/tensorflow/core/kernels/unicode_ops.cc)

assumes that the input_value/input_splits pair specify a valid sparse tensor.

Patches

We have patched the issue in GitHub commit [51300ba1cc2f487aefec6e6631fef03b0e08b298](https://github.com/tensorflow/tensorflow/commit/51300ba1cc2f487aefec6e6631fef03b0e08b298).

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.

For more information

Please consult [our security guide](https://github.com/tensorflow/tensorflow/blob/master/SECURITY.md) for more information regarding the security model and how to contact us with issues and questions.

Attribution

This vulnerability has been reported by Ying Wang and Yakun Zhang of...

Affected versions

PackageAffectedFixed in
tensorflow
PyPI
< 2.1.42.1.4
>= 2.2.0, < 2.2.32.2.3
>= 2.3.0, < 2.3.32.3.3
>= 2.4.0, < 2.4.22.4.2
Details and references

### Impact An attacker can access data outside of bounds of heap allocated array in `tf.raw_ops.UnicodeEncode`: ```python import tensorflow as tf input_values = tf.constant([58], shape=[1], dtype=tf.int32) input_splits = tf.constant([[81, 101, 0]], shape=[3], dtype=tf.int32) output_encoding = "UTF-8" tf.raw_ops.UnicodeEncode( input_values=input_values, input_splits=input_splits, output_encoding=output_encoding) ``` This is because the [implementation](https://github.com/tensorflow/tensorflow/blob/472c1f12ad9063405737679d4f6bd43094e1d36d/tensorflow/core/kernels/unicode_ops.cc) assumes that the `input_value`/`input_splits` pair specify a valid sparse tensor. ### Patches We have patched the issue in GitHub commit [51300ba1cc2f487aefec6e6631fef03b0e08b298](https://github.com/tensorflow/tensorflow/commit/51300ba1cc2f487aefec6e6631fef03b0e08b298). 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. ### For more information Please consult [our security guide](https://github.com/tensorflow/tensorflow/blob/master/SECURITY.md) for more information regarding the security model and how to contact us with issues and questions. ### Attribution This vulnerability has been reported by Ying Wang and Yakun Zhang of Baidu X-Team.

CVSS 3.1
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L
Severity from
GitHub (reviewed advisory)
Weakness
CWE-125
Also known as
BIT-tensorflow-2021-29559, CVE-2021-29559, PYSEC-2021-196, PYSEC-2021-487, PYSEC-2021-685

More TensorFlow advisories

All TensorFlow