# CVE-2021-37644: TensorFlow std::abort in TensorListReserve

Source: https://junglewise.ai/threats/cve-2021-37644-tensorflow-std-abort-in-tensorlistreserve  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2021-08-12. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2021-37644 · Severity: low · CVSS 3.1 · Published 2021-08-12

TensorFlow's TensorListReserve operation fails to validate the num_elements parameter, allowing an attacker to pass a negative value that causes the runtime to crash. This denial-of-service vulnerability affects machine learning pipelines using TensorFlow, potentially disrupting model training, inference, or data processing workloads.

Technologies: [Google TensorFlow](https://junglewise.ai/threats/technologies/tensorflow), [tensorflow (PyPI)](https://junglewise.ai/threats/technologies/pypi-tensorflow), [tensorflow-cpu (PyPI)](https://junglewise.ai/threats/technologies/tensorflow-cpu), [tensorflow-gpu (PyPI)](https://junglewise.ai/threats/technologies/tensorflow-gpu). Vendors: [Google](https://junglewise.ai/threats/vendors/google), [PyPI](https://junglewise.ai/threats/vendors/pypi).

## Quick answers

**Is CVE-2021-37644 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2021-37644 being exploited in the wild.

**How severe is CVE-2021-37644?** Low severity, with a CVSS score of 3.1, published 12 August 2021.

**Which products and versions are affected?** Google TensorFlow < 2.6.0; fixed in 2.3.4, 2.4.3, 2.5.1, 2.6.0+; tensorflow (PyPI) GIT:introduced=0,fixed=8a6e874437670045e6c7dc6154c7412b4a2135e2|ECOSYSTEM:introduced=2.3.0,fixed=2.3.4,introduced=2.4.0,fixed=2.4.3; tensorflow-cpu (PyPI) GIT:introduced=0,fixed=8a6e874437670045e6c7dc6154c7412b4a2135e2|ECOSYSTEM:introduced=2.3.0,fixed=2.3.4,introduced=2.4.0,fixed=2.4.3; tensorflow-gpu (PyPI) GIT:introduced=0,fixed=8a6e874437670045e6c7dc6154c7412b4a2135e2|ECOSYSTEM:introduced=2.3.0,fixed=2.3.4,introduced=2.4.0,fixed=2.4.3.

**Is there a fix for CVE-2021-37644?** Yes. tensorflow (PyPI): upgrade to 2.4.3 or later; tensorflow-cpu (PyPI): upgrade to 2.4.3 or later; tensorflow-gpu (PyPI): upgrade to 2.4.3 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2021-37644 attacked?** It is attacked with local access, in a software library.

**Am I affected by CVE-2021-37644?** Check whether you run Google TensorFlow, tensorflow (PyPI), tensorflow-cpu (PyPI) or one of the others listed at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- tensorflow (PyPI): upgrade to 2.4.3 or later

  ```sh
  pip install "tensorflow>=2.4.3"
  ```

- tensorflow-cpu (PyPI): upgrade to 2.4.3 or later

  ```sh
  pip install "tensorflow-cpu>=2.4.3"
  ```

- tensorflow-gpu (PyPI): upgrade to 2.4.3 or later

  ```sh
  pip install "tensorflow-gpu>=2.4.3"
  ```


## Technical details

The tf.raw_ops.TensorListReserve operation in TensorFlow performs an unchecked std::vector.resize() call with a user-supplied num_elements parameter. An attacker providing a negative value triggers an abort condition in the C++ standard library. The vulnerability exists in versions prior to 2.6.0 (with cherry-picked fixes in 2.3.4, 2.4.3, and 2.5.1). Exploitation requires the ability to invoke TensorFlow operations with attacker-controlled input (local access or remote code execution capability in the application layer). The impact is a process crash (denial of service).

## Affected products

- Google TensorFlow < 2.6.0; fixed in 2.3.4, 2.4.3, 2.5.1, 2.6.0+
- Google TensorFlow CPU < 2.3.4, 2.4.0–2.4.2, 2.5.0
- Google TensorFlow GPU < 2.3.4, 2.4.0–2.4.2, 2.5.0

## Identifiers

- CVE-2021-37644
- GHSA-27j5-4p9v-pp67
- PYSEC-2021-266
- PYSEC-2021-557
- PYSEC-2021-755

## Timeline

- 2021-08-11: disclosed
- 2021-08-25: patched: Fix included in TensorFlow 2.6.0 and cherry-picked to 2.3.4, 2.4.3, 2.5.1

## References

- [https://github.com/tensorflow/tensorflow/security/advisories/GHSA-27j5-4p9v-pp67](https://github.com/tensorflow/tensorflow/security/advisories/GHSA-27j5-4p9v-pp67)

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