Division by zero in TFLite's implementation of `SpaceToDepth`
Low2.5CVE-2021-29587 · Published May 21, 2021 · updated Jul 8, 2026
### Impact The `Prepare` step of the `SpaceToDepth` TFLite operator [does not check for 0 before division](https://github.com/tensorflow/tensorflow/blob/5f7975d09eac0f10ed8a17dbb6f5964977725adc/tensorflow/lite/kernels/space_to_depth.cc#L63-L67). ```cc const int block_size = params->block_size; const int input_height = input->dims->data[1]; const int input_width = input->dims->data[2]; int output_height = input_height / block_size; int output_width = input_width / block_size; ``` An attacker can craft a model such that `params->block_size` would be zero. ### Patches We have patched the issue in GitHub commit [0d45ea1ca641b21b73bcf9c00e0179cda284e7e7](https://github.com/tensorflow/tensorflow/commit/0d45ea1ca641b21b73bcf9c00e0179cda284e7e7). 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](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. ##...
Affected versions
| Package | Affected | Fixed in |
|---|---|---|
| tensorflow PyPI | < 2.1.4 | 2.1.4 |
| >= 2.2.0, < 2.2.3 | 2.2.3 | |
| >= 2.3.0, < 2.3.3 | 2.3.3 | |
| >= 2.4.0, < 2.4.2 | 2.4.2 |
Details and references
### Impact The `Prepare` step of the `SpaceToDepth` TFLite operator [does not check for 0 before division](https://github.com/tensorflow/tensorflow/blob/5f7975d09eac0f10ed8a17dbb6f5964977725adc/tensorflow/lite/kernels/space_to_depth.cc#L63-L67). ```cc const int block_size = params->block_size; const int input_height = input->dims->data[1]; const int input_width = input->dims->data[2]; int output_height = input_height / block_size; int output_width = input_width / block_size; ``` An attacker can craft a model such that `params->block_size` would be zero. ### Patches We have patched the issue in GitHub commit [0d45ea1ca641b21b73bcf9c00e0179cda284e7e7](https://github.com/tensorflow/tensorflow/commit/0d45ea1ca641b21b73bcf9c00e0179cda284e7e7). 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](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 members of the Aivul Team from Qihoo 360.
- CVSS 3.1
- CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L
- Severity from
- GitHub (reviewed advisory)
- Weakness
- CWE-369
- Also known as
- BIT-tensorflow-2021-29587, CVE-2021-29587, PYSEC-2021-224, PYSEC-2021-515, PYSEC-2021-713
- github.com/tensorflow/tensorflow/security/advisories/GHSA-j7rm-8ww4-xx2g
- nvd.nist.gov/vuln/detail/CVE-2021-29587
- github.com/tensorflow/tensorflow/commit/0d45ea1ca641b21b73bcf9c00e0179cda284e7e7
- github.com/pypa/advisory-database/tree/main/vulns/tensorflow-cpu/PYSEC-2021-515.yaml
- github.com/pypa/advisory-database/tree/main/vulns/tensorflow-gpu/PYSEC-2021-713.yaml
- github.com/pypa/advisory-database/tree/main/vulns/tensorflow/PYSEC-2021-224.yaml
- github.com/tensorflow/tensorflow
- github.com/tensorflow/tensorflow/blob/5f7975d09eac0f10ed8a17dbb6f5964977725adc/tensorflow/lite/kernels/space_to_depth.cc#L63-L67
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