CVE-2021-29617: Denial of Service in TensorFlow

tensorflow-cpu Updated 02 Oct 2025

Summary

14/05/2021

Disclosed on

CVE-2021-29617

CVE

Yes i

Fix available

Unrated

Severity

Not published

CVSS Score

CVE-2021-29617: TensorFlow is an end-to-end open source platform for machine learning. Affects tensorflow-cpu across 5 version ranges.

>= 2.2.0, < 2.3.0rc0 < 2.2.0rc0 >= 2.3.0, < 2.3.4 >= 2.4.0, < 2.4.3 < 890f7164b70354c57d40eda52dcdd7658677c09f

Fixed in 4 releases; the minimum fixed version depends on the release line you run. How to fix ↓

Also tracked for

tensorflow · Bitnami
tensorflow · PyPI
tensorflow · PyPI
tensorflow-gpu · PyPI

The same CVE-2021-29617 is tracked separately for each ecosystem and vendor. Its fix information is the same; the package and affected versions differ.

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Background

TensorFlow is an end-to-end open source platform for machine learning. It provides a comprehensive ecosystem of tools, libraries, and resources for developing and deploying machine learning models. TensorFlow is widely used in various domains, including research, industry, and academia. It offers support for both CPU and GPU computations, allowing users to leverage the power of hardware acceleration. However, a vulnerability has been discovered in TensorFlow that can lead to a denial of service (DoS) attack.

Vulnerability Detail

The vulnerability exists in the tf.strings.substr function of TensorFlow. An attacker can exploit this vulnerability by providing invalid arguments to the function, causing a CHECK-fail and resulting in a DoS condition. The impact of this vulnerability can be severe, as it can disrupt the availability of TensorFlow-based applications and services. The vulnerability has been assigned the CVE identifier CVE-2021-29617.

How To Fix

Latest published version: 2.21.0 as of 22 Oct 2026

pip install --upgrade "tensorflow-cpu==2.21.0"

Upgrading to it may include breaking changes; the versions below are the minimum fixed release for this vulnerability.

If you can't move to the latest

The minimum fixed version depends on the release line you run.

< 2.2.0rc0 2.2.0rc0

pip install --upgrade "tensorflow-cpu==2.2.0rc0"

>= 2.2.0, < 2.3.0rc0 2.3.0rc0

pip install --upgrade "tensorflow-cpu==2.3.0rc0"

>= 2.3.0, < 2.3.4 2.3.4

pip install --upgrade "tensorflow-cpu==2.3.4"

>= 2.4.0, < 2.4.3 2.4.3

pip install --upgrade "tensorflow-cpu==2.4.3"

Tip — Not sure which release line you're on? Vulert can find the fix for the version you are using. Scan free →

Workaround

As a temporary workaround, users can avoid using the vulnerable tf.strings.substr function or ensure that the function is called with valid arguments. It is recommended to review the codebase and identify any instances where the vulnerable function is used. If possible, consider using alternative functions or approaches to achieve the desired functionality.

Conclusion

In conclusion, a vulnerability has been discovered in TensorFlow that can lead to a denial of service (DoS) condition. Users are advised to update their TensorFlow installations to the latest patched version as soon as it becomes available. It is also recommended to review the codebase for any usage of the vulnerable tf.strings.substr function and consider using alternative approaches if possible. For further support on vulnerability remediation, you can reach out to DevNack.com.

See every vulnerability recorded for tensorflow-cpu →

FAQ

What is TensorFlow?

TensorFlow is an open source platform for machine learning that provides a comprehensive set of tools and resources for developing and deploying machine learning models.

What is the impact of this vulnerability?

The vulnerability can lead to a denial of service (DoS) condition in TensorFlow-based applications and services, potentially disrupting their availability.

How can I fix this vulnerability?

The vulnerability will be fixed in TensorFlow 2.5.0. Users should update their TensorFlow installations to the latest patched version as soon as it becomes available.

Are there any workarounds available?

As a temporary workaround, users can avoid using the vulnerable tf.strings.substr function or ensure that it is called with valid arguments.

Can I check if my application is affected by this vulnerability?

Yes, you can use Vulert's playground at Vulert Scanner to check if your application is affected by this vulnerability. Vulert monitors and alerts in real-time for open-source vulnerabilities without requiring access to the code or installation.

References

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