{"cve":"CVE-2021-37646","nvd":{"published":"2021-08-12T21:15:07.983","modified":"2026-06-17T04:00:53.887","status":"Modified","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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","score":5.5},"cwes":["CWE-681"],"references":["https://github.com/tensorflow/tensorflow/commit/c283e542a3f422420cfdb332414543b62fc4e4a5","https://github.com/tensorflow/tensorflow/security/advisories/GHSA-h6jh-7gv5-28vg","https://github.com/tensorflow/tensorflow/commit/c283e542a3f422420cfdb332414543b62fc4e4a5","https://github.com/tensorflow/tensorflow/security/advisories/GHSA-h6jh-7gv5-28vg"],"products":["google:tensorflow"],"source":"nvd","synced_at":"2026-10-19T21:21:57.125947417+00:00"},"epss":{"cve":"CVE-2021-37646","score":0.00154,"percentile":0.04532,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-h6jh-7gv5-28vg","url":"https://osv.dev/vulnerability/GHSA-h6jh-7gv5-28vg","summary":"Bad alloc in `StringNGrams` caused by integer conversion","modified":"2026-07-08T06:29:33.587436290Z","packages":[{"ecosystem":"PyPI","name":"tensorflow","purl":"pkg:pypi/tensorflow","ranges":["<2.3.4"],"fixed":["2.3.4"]},{"ecosystem":"PyPI","name":"tensorflow","purl":"pkg:pypi/tensorflow","ranges":[">=2.4.0 <2.4.3"],"fixed":["2.4.3"]},{"ecosystem":"PyPI","name":"tensorflow","purl":"pkg:pypi/tensorflow","ranges":[">=2.5.0 <2.5.1"],"fixed":["2.5.1"]},{"ecosystem":"PyPI","name":"tensorflow-cpu","purl":"pkg:pypi/tensorflow-cpu","ranges":["<2.3.4"],"fixed":["2.3.4"]},{"ecosystem":"PyPI","name":"tensorflow-cpu","purl":"pkg:pypi/tensorflow-cpu","ranges":[">=2.4.0 <2.4.3"],"fixed":["2.4.3"]},{"ecosystem":"PyPI","name":"tensorflow-cpu","purl":"pkg:pypi/tensorflow-cpu","ranges":[">=2.5.0 <2.5.1"],"fixed":["2.5.1"]},{"ecosystem":"PyPI","name":"tensorflow-gpu","purl":"pkg:pypi/tensorflow-gpu","ranges":["<2.3.4"],"fixed":["2.3.4"]},{"ecosystem":"PyPI","name":"tensorflow-gpu","purl":"pkg:pypi/tensorflow-gpu","ranges":[">=2.4.0 <2.4.3"],"fixed":["2.4.3"]},{"ecosystem":"PyPI","name":"tensorflow-gpu","purl":"pkg:pypi/tensorflow-gpu","ranges":[">=2.5.0 <2.5.1"],"fixed":["2.5.1"]}]},{"id":"PYSEC-2021-268","url":"https://osv.dev/vulnerability/PYSEC-2021-268","summary":"","modified":"2023-12-06T01:01:21.910311Z","packages":[{"ecosystem":"PyPI","name":"tensorflow","purl":"pkg:pypi/tensorflow","ranges":[">=2.3.0 <2.3.4",">=2.4.0 <2.4.3"],"fixed":["2.3.4","2.4.3"]}]},{"id":"PYSEC-2021-559","url":"https://osv.dev/vulnerability/PYSEC-2021-559","summary":"","modified":"2023-12-06T01:01:21.910311Z","packages":[{"ecosystem":"PyPI","name":"tensorflow-cpu","purl":"pkg:pypi/tensorflow-cpu","ranges":[">=2.3.0 <2.3.4",">=2.4.0 <2.4.3"],"fixed":["2.3.4","2.4.3"]}]},{"id":"PYSEC-2021-757","url":"https://osv.dev/vulnerability/PYSEC-2021-757","summary":"","modified":"2023-12-06T01:01:21.910311Z","packages":[{"ecosystem":"PyPI","name":"tensorflow-gpu","purl":"pkg:pypi/tensorflow-gpu","ranges":[">=2.3.0 <2.3.4",">=2.4.0 <2.4.3"],"fixed":["2.3.4","2.4.3"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}