Integer overflow in TFLite concatentation
Medium6.3CVE-2021-29601 · Published May 21, 2021 · updated Jul 8, 2026
### Impact The TFLite implementation of concatenation is [vulnerable to an integer overflow issue](https://github.com/tensorflow/tensorflow/blob/7b7352a724b690b11bfaae2cd54bc3907daf6285/tensorflow/lite/kernels/concatenation.cc#L70-L76): ```cc for (int d = 0; d < t0->dims->size; ++d) { if (d == axis) { sum_axis += t->dims->data[axis]; } else { TF_LITE_ENSURE_EQ(context, t->dims->data[d], t0->dims->data[d]); } } ``` An attacker can craft a model such that the dimensions of one of the concatenation input overflow the values of `int`. TFLite uses `int` to represent tensor dimensions, whereas TF uses `int64`. Hence, valid TF models can trigger an integer overflow when converted to TFLite format. ### Patches We have patched the issue in GitHub commit [4253f96a58486ffe84b61c0415bb234a4632ee73](https://github.com/tensorflow/tensorflow/commit/4253f96a58486ffe84b61c0415bb234a4632ee73). 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...
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 TFLite implementation of concatenation is [vulnerable to an integer overflow issue](https://github.com/tensorflow/tensorflow/blob/7b7352a724b690b11bfaae2cd54bc3907daf6285/tensorflow/lite/kernels/concatenation.cc#L70-L76): ```cc for (int d = 0; d < t0->dims->size; ++d) { if (d == axis) { sum_axis += t->dims->data[axis]; } else { TF_LITE_ENSURE_EQ(context, t->dims->data[d], t0->dims->data[d]); } } ``` An attacker can craft a model such that the dimensions of one of the concatenation input overflow the values of `int`. TFLite uses `int` to represent tensor dimensions, whereas TF uses `int64`. Hence, valid TF models can trigger an integer overflow when converted to TFLite format. ### Patches We have patched the issue in GitHub commit [4253f96a58486ffe84b61c0415bb234a4632ee73](https://github.com/tensorflow/tensorflow/commit/4253f96a58486ffe84b61c0415bb234a4632ee73). 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:H/A:H
- Severity from
- GitHub (reviewed advisory)
- Weakness
- CWE-190
- Also known as
- BIT-tensorflow-2021-29601, CVE-2021-29601, PYSEC-2021-238, PYSEC-2021-529, PYSEC-2021-727
- github.com/tensorflow/tensorflow/security/advisories/GHSA-9c84-4hx6-xmm4
- nvd.nist.gov/vuln/detail/CVE-2021-29601
- github.com/tensorflow/tensorflow/commit/4253f96a58486ffe84b61c0415bb234a4632ee73
- github.com/pypa/advisory-database/tree/main/vulns/tensorflow-cpu/PYSEC-2021-529.yaml
- github.com/pypa/advisory-database/tree/main/vulns/tensorflow-gpu/PYSEC-2021-727.yaml
- github.com/pypa/advisory-database/tree/main/vulns/tensorflow/PYSEC-2021-238.yaml
- github.com/tensorflow/tensorflow
- github.com/tensorflow/tensorflow/blob/7b7352a724b690b11bfaae2cd54bc3907daf6285/tensorflow/lite/kernels/concatenation.cc#L70-L76
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