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CVE-2021-29559

Heap OOB access in unicode ops

2.5 LowFix available

TensorFlow is an end-to-end open source platform for machine learning. An attacker can access data outside of bounds of heap allocated array in tf.raw_ops.UnicodeEncode. 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. 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.

Attack profile

How easy it is to exploit

Attack vector
Local
Complexity
High
Privileges needed
Low
User interaction
None

What an attacker can affect

Confidentiality
None
Integrity
None
Availability
Low

Exploit likelihood

0.20%Down 0.4 points since May 15, 2021
90%50%10%1%

What each source reports

CVE List Score used 2.5

Heap OOB access in unicode ops

TensorFlow is an end-to-end open source platform for machine learning. An attacker can access data outside of bounds of heap allocated array in tf.raw_ops.UnicodeEncode. 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. 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.

Record
CVE-2021-29559
CVSS 3.1
2.5 LowCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L
Weakness
CWE-125
Updated
2026-11-02
EUVDEUVD-2021-0300 2.5

TensorFlow is an end-to-end open source platform for machine learning. An attacker can access data outside of bounds of heap allocated array in tf.raw_ops.UnicodeEncode. 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. 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.

Record
EUVD-2021-0300
CVSS 3.1
2.5 LowCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L
Updated
2026-11-03
GitHub AdvisoriesGHSA-59q2-x2qc-4c97 2.0

Heap OOB access in unicode ops

Impact

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

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

Patches

We have patched the issue in GitHub 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 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.

Record
GHSA-59q2-x2qc-4c97
CVSS 4.0
2.0 LowCVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
CVSS 3.1
2.5 LowCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L
Weakness
CWE-125
Updated
2026-11-02
NVD 2.5

TensorFlow is an end-to-end open source platform for machine learning. An attacker can access data outside of bounds of heap allocated array in tf.raw_ops.UnicodeEncode. 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. 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.

Record
CVE-2021-29559
CVSS 3.1
2.5 LowCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L
CVSS 3.1
7.1 HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
CVSS 2.0
3.6 LowAV:L/AC:L/Au:N/C:P/I:N/A:P
Weakness
CWE-125
Updated
2026-11-02
OSV 7.1

TensorFlow is an end-to-end open source platform for machine learning. An attacker can access data outside of bounds of heap allocated array in tf.raw_ops.UnicodeEncode. 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. 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.

Record
CVE-2021-29559
CVSS 3.1
7.1 HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
Updated
2026-11-02
OSVGHSA-59q2-x2qc-4c97 2.0

Heap OOB access in unicode ops

Impact

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

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

Patches

We have patched the issue in GitHub 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 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.

Record
GHSA-59q2-x2qc-4c97
CVSS 4.0
2.0 LowCVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
CVSS 3.1
2.5 LowCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L
Weakness
CWE-125
Updated
2026-11-02
Show 4 moreShow less
OSVBIT-tensorflow-2021-29559 No score

Heap OOB access in unicode ops

TensorFlow is an end-to-end open source platform for machine learning. An attacker can access data outside of bounds of heap allocated array in tf.raw_ops.UnicodeEncode. 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. 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.

Record
BIT-tensorflow-2021-29559
Updated
2026-11-02
OSVPYSEC-2021-196 No score

TensorFlow is an end-to-end open source platform for machine learning. An attacker can access data outside of bounds of heap allocated array in tf.raw_ops.UnicodeEncode. 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. 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.

Record
PYSEC-2021-196
Updated
2026-11-02
OSVPYSEC-2021-487 No score

TensorFlow is an end-to-end open source platform for machine learning. An attacker can access data outside of bounds of heap allocated array in tf.raw_ops.UnicodeEncode. 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. 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.

Record
PYSEC-2021-487
Updated
2026-11-02
OSVPYSEC-2021-685 No score

TensorFlow is an end-to-end open source platform for machine learning. An attacker can access data outside of bounds of heap allocated array in tf.raw_ops.UnicodeEncode. 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. 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.

Record
PYSEC-2021-685
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
tensorflow
PyPI
 before 2.1.4
2.1.4
tensorflow
PyPI
 2.2.0 up to 2.2.3
2.2.3
tensorflow
PyPI
 2.3.0 up to 2.3.3
2.3.3
tensorflow
PyPI
 2.4.0 up to 2.4.2
2.4.2
tensorflow-cpu
PyPI
 before 2.1.4
2.1.4
tensorflow-cpu
PyPI
 2.2.0 up to 2.2.3
2.2.3
tensorflow-cpu
PyPI
 2.3.0 up to 2.3.3
2.3.3
tensorflow-cpu
PyPI
 2.4.0 up to 2.4.2
2.4.2
tensorflow-gpu
PyPI
 before 2.1.4
2.1.4
tensorflow-gpu
PyPI
 2.2.0 up to 2.2.3
2.2.3
Show 18 moreShow less
Affected packages
PackageAffectedFixed
tensorflow-gpu
PyPI
 2.3.0 up to 2.3.3
2.3.3
tensorflow-gpu
PyPI
 2.4.0 up to 2.4.2
2.4.2
tensorflow
Bitnami
 before 2.1.4, 2.2.0 up to 2.2.3, 2.3.0 up to 2.3.3, 2.4.0 up to 2.4.2
2.1.42.2.32.3.32.4.2
tensorflow
PyPI
 before 2.1.4, plus listed versions
0.12.00.12.11.0.01.0.11.1.0
Show 35 moreShow less
1.10.01.10.11.11.01.12.01.12.21.12.31.13.11.13.21.14.01.15.01.15.21.15.31.15.41.15.51.2.01.2.11.3.01.4.01.4.11.5.01.5.11.6.01.7.01.7.11.8.01.9.02.0.02.0.12.0.22.0.32.0.42.1.02.1.12.1.22.1.3
2.1.4
tensorflow
PyPI
 2.2.0 up to 2.2.3, plus listed versions
2.2.12.2.2
2.2.3
tensorflow
PyPI
 2.3.0 up to 2.3.3, plus listed versions
2.3.12.3.2
2.3.3
tensorflow
PyPI
 2.4.0 up to 2.4.2, plus listed versions
2.4.1
2.4.2
tensorflow-cpu
PyPI
 before 2.1.4, plus listed versions
1.15.02.1.02.1.12.1.22.1.3
2.1.4
tensorflow-cpu
PyPI
 2.2.0 up to 2.2.3, plus listed versions
2.2.12.2.2
2.2.3
tensorflow-cpu
PyPI
 2.3.0 up to 2.3.3, plus listed versions
2.3.12.3.2
2.3.3
tensorflow-cpu
PyPI
 2.4.0 up to 2.4.2, plus listed versions
2.4.1
2.4.2
tensorflow-gpu
PyPI
 before 2.1.4, plus listed versions
0.12.00.12.11.0.01.0.11.1.0
Show 35 moreShow less
1.10.01.10.11.11.01.12.01.12.21.12.31.13.11.13.21.14.01.15.01.15.21.15.31.15.41.15.51.2.01.2.11.3.01.4.01.4.11.5.01.5.11.6.01.7.01.7.11.8.01.9.02.0.02.0.12.0.22.0.32.0.42.1.02.1.12.1.22.1.3
2.1.4
tensorflow-gpu
PyPI
 2.2.0 up to 2.2.3, plus listed versions
2.2.12.2.2
2.2.3
tensorflow-gpu
PyPI
 2.3.0 up to 2.3.3, plus listed versions
2.3.12.3.2
2.3.3
tensorflow-gpu
PyPI
 2.4.0 up to 2.4.2, plus listed versions
2.4.1
2.4.2
tensorflow
PyPI
 before 2.1.4, 2.2.0 up to 2.2.3, 2.3.0 up to 2.3.3, 2.4.0 up to 2.4.2, plus listed versions
0.12.00.12.0rc00.12.0rc10.12.11.0.0
Show 45 moreShow less
1.0.11.1.01.1.0rc01.1.0rc11.1.0rc21.10.01.10.0rc01.10.0rc11.10.11.11.01.11.0rc01.11.0rc11.11.0rc21.12.01.12.0rc01.12.0rc11.12.0rc21.12.21.12.31.13.0rc01.13.0rc11.13.0rc21.13.11.13.21.14.01.14.0rc01.14.0rc11.15.01.15.0rc01.15.0rc11.15.0rc21.15.0rc31.15.21.15.31.15.41.15.51.2.01.2.0rc01.2.0rc11.2.0rc21.2.11.3.01.3.0rc01.3.0rc11.3.0rc2
2.1.42.2.32.3.32.4.2
tensorflow-cpu
PyPI
 before 2.1.4, 2.2.0 up to 2.2.3, 2.3.0 up to 2.3.3, 2.4.0 up to 2.4.2, plus listed versions
1.15.02.1.02.1.12.1.22.1.3
Show 5 moreShow less
2.2.12.2.22.3.12.3.22.4.1
2.1.42.2.32.3.32.4.2
tensorflow-gpu
PyPI
 before 2.1.4, 2.2.0 up to 2.2.3, 2.3.0 up to 2.3.3, 2.4.0 up to 2.4.2, plus listed versions
0.12.00.12.11.0.01.0.11.1.0
Show 40 moreShow less
1.10.01.10.11.11.01.12.01.12.21.12.31.13.11.13.21.14.01.15.01.15.21.15.31.15.41.15.51.2.01.2.11.3.01.4.01.4.11.5.01.5.11.6.01.7.01.7.11.8.01.9.02.0.02.0.12.0.22.0.32.0.42.1.02.1.12.1.22.1.32.2.12.2.22.3.12.3.22.4.1
2.1.42.2.32.3.32.4.2

History

History
RecordedChangedSources
aliasesEUVD
first indexedCVE List, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2021-29559 is a low vulnerability (CVSS 2.5) in Google Tensorflow, published May 14, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.20%, the 9th percentile. Fixed in tensorflow 2.1.4.

References

This page doesn't list everything

Left out here: 45 versions. The JSON record has them.

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