CVE-2021-37646
Bad alloc in `StringNGrams` caused by integer conversion in TensorFlow
Description
TensorFlow is an end-to-end open source platform for machine learning. In affected versions the implementation of `tf.raw_ops.StringNGrams` is vulnerable to an integer overflow issue caused by converting a signed integer value to an unsigned one and then allocating memory based on this value. The [implementation](https://github.com/tensorflow/tensorflow/blob/8d72537c6abf5a44103b57b9c2e22c14f5f49698/tensorflow/core/kernels/string_ngrams_op.cc#L184) calls `reserve` on a `tstring` with a value that sometimes can be negative if user supplies negative `ngram_widths`. The `reserve` method calls `TF_TString_Reserve` which has an `unsigned long` argument for the size of the buffer. Hence, the implicit conversion transforms the negative value to a large integer. We have patched the issue in GitHub commit c283e542a3f422420cfdb332414543b62fc4e4a5. 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.
How to fix CVE-2021-37646
To remediate CVE-2021-37646, upgrade the affected package to a fixed version below.
- —upgrade to 2.3.4 or later
- —upgrade to 2.3.4 or later
- —upgrade to c283e542a3f422420cfdb332414543b62fc4e4a5 or later
- —upgrade to c283e542a3f422420cfdb332414543b62fc4e4a5 or later
- —upgrade to 2.3.4 or later
- —upgrade to c283e542a3f422420cfdb332414543b62fc4e4a5 or later
- —upgrade to 2.3.4 or later
Is CVE-2021-37646 being exploited?
Low — EPSS is 0.0%, meaning exploitation activity has not been observed at scale.
Affected packages (7)
- >= 2.3.0, < 2.3.4, >= 2.4.0, < 2.4.3, >= 2.5.0, < 2.5.1
- from 0, < 2.3.4
- from 0, < c283e542a3f422420cfdb332414543b62fc4e4a5 | >= 2.3.0, < 2.3.4, >= 2.4.0, < 2.4.3
- from 0, < c283e542a3f422420cfdb332414543b62fc4e4a5 | >= 2.3.0, < 2.3.4, >= 2.4.0, < 2.4.3
- from 0, < 2.3.4
- from 0, < c283e542a3f422420cfdb332414543b62fc4e4a5 | >= 2.3.0, < 2.3.4, >= 2.4.0, < 2.4.3
- from 0, < 2.3.4
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 4.0 | — | CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N |
| osv | CVSS 3.1 | MEDIUM5.5 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H |