Security advisory

{
  "id": "c44a553086b7f44585d6c285a6d30a1fa276e63ffcdb97bafc196151c9bb88d8",
  "url": "https://osv.dev/vulnerability/CVE-2021-37646",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2021-37646",
    "summary": "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.",
    "evidence": "osv:CVE-2021-37646",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2021-37646",
      "aliases": [
        "BIT-tensorflow-2021-37646",
        "CVE-2021-37646",
        "GHSA-h6jh-7gv5-28vg",
        "PYSEC-2021-268",
        "PYSEC-2021-559",
        "PYSEC-2021-757"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/tensorflow/tensorflow",
              "type": "GIT",
              "events": [
                {
                  "introduced": "b36436b087bd8e8701ef51718179037cccdfc26e"
                },
                {
                  "fixed": "7462dcaae1e8cfe1dfd0c62dd6083f9749a9d827"
                },
                {
                  "introduced": "582c8d236cb079023657287c318ff26adb239002"
                },
                {
                  "fixed": "4c0b84bf2a714bcdd18da1f1f94d533d72399d52"
                },
                {
                  "introduced": "a4dfb8d1a71385bd6d122e4f27f86dcebb96712d"
                },
                {
                  "last_affected": "5368d50428b30b7c9ccd038aec65d09252d16596"
                },
                {
                  "fixed": "c283e542a3f422420cfdb332414543b62fc4e4a5"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:google:tensorflow:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "2.3.0"
                      },
                      {
                        "fixed": "2.3.4"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "cpe": "cpe:2.3:a:google:tensorflow:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "2.4.0"
                      },
                      {
                        "fixed": "2.4.3"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "cpe": "cpe:2.3:a:google:tensorflow:2.5.0:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "2.5.0"
                      },
                      {
                        "last_affected": "2.5.0"
                      }
                    ],
                    "source": "CPE_STRING"
                  },
                  {
                    "cpe": "cpe:2.3:a:google:tensorflow:2.6.0:rc0:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "2.6.0-rc0"
                      },
                      {
                        "last_affected": "2.6.0-rc0"
                      }
                    ],
                    "source": "CPE_STRING"
                  },
                  {
                    "cpe": "cpe:2.3:a:google:tensorflow:2.6.0:rc1:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "2.6.0-rc1"
                      },
                      {
                        "last_affected": "2.6.0-rc1"
                      }
                    ],
                    "source": "CPE_STRING"
                  },
                  {
                    "cpe": "cpe:2.3:a:google:tensorflow:2.6.0:rc2:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "2.6.0-rc2"
                      },
                      {
                        "last_affected": "2.6.0-rc2"
                      }
                    ],
                    "source": "CPE_STRING"
                  },
                  {
                    "range": [
                      {
                        "fixed": "c283e542a3f422420cfdb332414543b62fc4e4a5"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "versions": [
            "2.5.0",
            "2.6.0-rc0",
            "2.6.0-rc1",
            "2.6.0-rc2",
            "v2.3.3",
            "v2.4.2",
            "v2.3.2",
            "v2.4.1",
            "v2.4.0",
            "v2.3.1",
            "v2.3.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-37646.json",
            "vanir_signatures": [
              {
                "id": "CVE-2021-37646-f8967422",
                "digest": {
                  "threshold": 0.9,
                  "line_hashes": [
                    "285621891283101487319147839348099093086",
                    "298920372003464589597498879960503880894",
                    "276814498817984533453586335083049431762",
                    "182428655347205365162753629093306997039"
                  ]
                },
                "source": "https://github.com/tensorflow/tensorflow/commit/c283e542a3f422420cfdb332414543b62fc4e4a5",
                "target": {
                  "file": "tensorflow/core/kernels/string_ngrams_op.cc"
                },
                "deprecated": false,
                "signature_type": "Line",
                "signature_version": "v1"
              }
            ],
            "vanir_signatures_modified": "2026-10-20T14:10:54Z"
          }
        }
      ],
      "modified": "2026-10-20T14:10:54.681127539Z",
      "provider": "osv",
      "references": [
        "https://github.com/tensorflow/tensorflow/security/advisories/GHSA-h6jh-7gv5-28vg",
        "https://github.com/tensorflow/tensorflow/commit/c283e542a3f422420cfdb332414543b62fc4e4a5"
      ],
      "provider_metadata": {}
    },
    "related_cves": [
      {
        "value": "CVE-2021-37646",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 388674,
  "published_at": "2021-08-12T21:15:07.983+00:00"
}