critical
9.3
CWE
502
Advisory Published
Advisory Published
Updated

CVE-2021-37678: Arbitrary code execution due to YAML deserialization

First published: Thu Aug 12 2021(Updated: )

### Impact TensorFlow and Keras can be tricked to perform arbitrary code execution when deserializing a Keras model from YAML format. ```python from tensorflow.keras import models payload = ''' !!python/object/new:type args: ['z', !!python/tuple [], {'extend': !!python/name:exec }] listitems: "__import__('os').system('cat /etc/passwd')" ''' models.model_from_yaml(payload) ``` The [implementation](https://github.com/tensorflow/tensorflow/blob/460e000de3a83278fb00b61a16d161b1964f15f4/tensorflow/python/keras/saving/model_config.py#L66-L104) uses `yaml.unsafe_load` which can perform arbitrary code execution on the input. ### Patches Given that YAML format support requires a significant amount of work, we have removed it for now. We have patched the issue in GitHub commit [23d6383eb6c14084a8fc3bdf164043b974818012](https://github.com/tensorflow/tensorflow/commit/23d6383eb6c14084a8fc3bdf164043b974818012). The fix will be included in TensorFlow 2.6.0. We will also cherrypick this commit on TensorFlow 2.5.1, TensorFlow 2.4.3, and TensorFlow 2.3.4, 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 Arjun Shibu.

Credit: security-advisories@github.com

Affected SoftwareAffected VersionHow to fix
pip/tensorflow-gpu=2.5.0
2.5.1
pip/tensorflow-gpu>=2.4.0<2.4.3
2.4.3
pip/tensorflow-gpu<2.3.4
2.3.4
pip/tensorflow-cpu=2.5.0
2.5.1
pip/tensorflow-cpu>=2.4.0<2.4.3
2.4.3
pip/tensorflow-cpu<2.3.4
2.3.4
pip/tensorflow=2.5.0
2.5.1
pip/tensorflow>=2.4.0<2.4.3
2.4.3
pip/tensorflow<2.3.4
2.3.4
TensorFlow Keras>=2.3.0<2.3.4
TensorFlow Keras>=2.4.0<2.4.3
TensorFlow Keras=2.5.0
TensorFlow Keras=2.6.0-rc0
TensorFlow Keras=2.6.0-rc1
TensorFlow Keras=2.6.0-rc2

Remedy

https://github.com/tensorflow/tensorflow/commit/23d6383eb6c14084a8fc3bdf164043b974818012

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Reference Links

Frequently Asked Questions

  • What is the severity of CVE-2021-37678?

    CVE-2021-37678 is classified as a high-severity vulnerability due to its potential for arbitrary code execution.

  • How do I fix CVE-2021-37678?

    To remediate CVE-2021-37678, upgrade TensorFlow to versions 2.5.1 or later.

  • Which versions of TensorFlow are affected by CVE-2021-37678?

    CVE-2021-37678 affects TensorFlow versions prior to 2.5.1, including 2.5.0, 2.4.x, and 2.3.x.

  • What type of vulnerability is CVE-2021-37678?

    CVE-2021-37678 is a deserialization vulnerability that could allow arbitrary code execution.

  • Can Keras models trigger CVE-2021-37678?

    Yes, CVE-2021-37678 can be triggered when deserializing Keras models from YAML format.

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