First published: Thu Aug 12 2021(Updated: )
### Impact The strided slice implementation in TFLite has a logic bug which can allow an attacker to trigger an infinite loop. This arises from newly introduced support for [ellipsis in axis definition](https://github.com/tensorflow/tensorflow/blob/149562d49faa709ea80df1d99fc41d005b81082a/tensorflow/lite/kernels/strided_slice.cc#L103-L122): ```cc for (int i = 0; i < effective_dims;) { if ((1 << i) & op_context->params->ellipsis_mask) { // ... int ellipsis_end_idx = std::min(i + 1 + num_add_axis + op_context->input_dims - begin_count, effective_dims); // ... for (; i < ellipsis_end_idx; ++i) { // ... } continue; } // ... ++i; } ``` An attacker can craft a model such that `ellipsis_end_idx` is smaller than `i` (e.g., always negative). In this case, the inner loop does not increase `i` and the `continue` statement causes execution to skip over the preincrement at the end of the outer loop. ### Patches We have patched the issue in GitHub commit [dfa22b348b70bb89d6d6ec0ff53973bacb4f4695](https://github.com/tensorflow/tensorflow/commit/dfa22b348b70bb89d6d6ec0ff53973bacb4f4695). The fix will be included in TensorFlow 2.6.0. This is the only affected version. ### 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.
Credit: security-advisories@github.com security-advisories@github.com
Affected Software | Affected Version | How to fix |
---|---|---|
Google TensorFlow | >=2.3.0<2.3.4 | |
Google TensorFlow | >=2.4.0<2.4.3 | |
Google TensorFlow | =2.5.0 | |
Google TensorFlow | =2.6.0-rc0 | |
Google TensorFlow | =2.6.0-rc1 | |
Google TensorFlow | =2.6.0-rc2 | |
pip/tensorflow-gpu | >=2.6.0rc0<2.6.0rc2 | 2.6.0rc2 |
pip/tensorflow-cpu | >=2.6.0rc0<2.6.0rc2 | 2.6.0rc2 |
pip/tensorflow | >=2.6.0rc0<2.6.0rc2 | 2.6.0rc2 |
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CVE-2021-37686 is classified as a high-severity vulnerability due to its potential to cause an infinite loop.
To fix CVE-2021-37686, update TensorFlow to version 2.6.0rc2 or later.
CVE-2021-37686 affects TensorFlow versions between 2.3.0 and 2.4.3, as well as specific 2.6.0 release candidates.
CVE-2021-37686 can lead to denial of service by causing applications to hang in an infinite loop.
Yes, CVE-2021-37686 impacts both TensorFlow CPU and GPU installations that are running affected versions.