CVE-2021-29535: TensorFlow-GPU Heap Buffer Overflow in QuantizedMul
Summary
CVE-2021-29535: TensorFlow is an end-to-end open source platform for machine learning. Affects tensorflow-gpu 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
< efea03b38fb8d3b81762237dc85e579cc5fc6e87
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-cpu · PyPI
The same CVE-2021-29535 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-GPU is a variant of TensorFlow that leverages the power of GPUs for accelerated computation. It allows users to train and run machine learning models on GPUs, which can significantly speed up the training process. However, TensorFlow-GPU is vulnerable to a heap buffer overflow in the QuantizedMul operation, which can be exploited by an attacker to execute arbitrary code or cause a denial of service.
Vulnerability Detail
The vulnerability in TensorFlow-GPU arises from a flaw in the implementation of the QuantizedMul operation. When invalid thresholds for quantization are passed as arguments, the implementation assumes that the arguments are valid scalars and tries to access the numeric value directly. However, if any of these tensors is empty, accessing the element at position 0 results in a heap buffer overflow. This can be exploited by an attacker to overwrite adjacent memory and potentially execute arbitrary code or crash the application. The vulnerability affects versions of TensorFlow-GPU up to 2.4.3.
How To Fix
Latest published version: 2.12.0 as of 22 Oct 2026
pip install --upgrade "tensorflow-gpu==2.12.0"
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.
-
< 2.2.0rc02.2.0rc0pip install --upgrade "tensorflow-gpu==2.2.0rc0" -
>= 2.2.0, < 2.3.0rc02.3.0rc0pip install --upgrade "tensorflow-gpu==2.3.0rc0" -
>= 2.3.0, < 2.3.42.3.4pip install --upgrade "tensorflow-gpu==2.3.4" -
>= 2.4.0, < 2.4.32.4.3pip install --upgrade "tensorflow-gpu==2.4.3"
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Workaround
As a workaround, users can avoid passing empty tensors as arguments to the QuantizedMul operation. By ensuring that the thresholds for quantization are valid and non-empty, the vulnerability can be mitigated. Here is an example of how to check for empty tensors before invoking the QuantizedMul operation:
import tensorflow as tf
def safe_quantized_mul(a, b, c, d):
if tf.size(a) == 0 or tf.size(b) == 0 or tf.size(c) == 0 or tf.size(d) == 0:
raise ValueError('Invalid thresholds for quantization')
else:
return tf.quantized_mul(a, b, c, d)
Conclusion
The heap buffer overflow vulnerability in TensorFlow-GPU's QuantizedMul operation can be mitigated by upgrading to the fixed versions or applying the backported fixes. Users should ensure that their TensorFlow-GPU installations are up to date to protect against potential exploitation. For further support on vulnerability remediation, please contact DevNack.com.
See every vulnerability recorded for tensorflow-gpu →
FAQ
TensorFlow is an open source platform for machine learning that provides a comprehensive ecosystem of tools, libraries, and resources for developing and deploying machine learning models.
TensorFlow-GPU is a variant of TensorFlow that leverages the power of GPUs for accelerated computation. It allows users to train and run machine learning models on GPUs, which can significantly speed up the training process.
The QuantizedMul operation in TensorFlow-GPU performs element-wise multiplication of quantized tensors. It is commonly used in machine learning models that involve quantization, which is the process of representing numerical values with a reduced precision to improve efficiency.
An attacker can exploit the vulnerability by passing empty tensors as arguments to the QuantizedMul operation. This triggers a heap buffer overflow, allowing the attacker to overwrite adjacent memory and potentially execute arbitrary code or crash the application.
To fix the vulnerability, users should upgrade their TensorFlow-GPU installation to version 2.5.0 or later. Alternatively, they can install the backported fixes for versions 2.4.2, 2.3.3, 2.2.3, and 2.1.4. The updated versions can be obtained from the official TensorFlow website or through the package manager.
References
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