Security advisory

{
  "id": "fe6e9c8ccda4f3c712063e6420fb4b0e1803c5d5030fb36bd98f2230b1c6812d",
  "url": "https://osv.dev/vulnerability/CVE-2016-9243",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2016-9243",
    "summary": "HKDF in cryptography before 1.5.2 returns an empty byte-string if used with a length less than algorithm.digest_size.",
    "evidence": "osv:CVE-2016-9243",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2016-9243",
      "aliases": [
        "CVE-2016-9243",
        "GHSA-q3cj-2r34-2cwc",
        "PYSEC-2017-8"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/pyca/cryptography",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "last_affected": "cad77746539f504d53eb1bf9b278ec081ab8040a"
                },
                {
                  "fixed": "b924696b2e8731f39696584d12cceeb3aeb2d874"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:cryptography.io:cryptography:*:*:*:*:*:python:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "last_affected": "1.5.2"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "range": [
                      {
                        "fixed": "b924696b2e8731f39696584d12cceeb3aeb2d874"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "versions": [
            "1.5.2",
            "1.5.1",
            "1.5",
            "1.4",
            "1.3",
            "1.2",
            "1.1",
            "1.0",
            "0.9",
            "0.8",
            "0.7",
            "0.6",
            "0.5.1",
            "0.5",
            "0.4",
            "0.3",
            "0.2",
            "0.1"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2016-9243.json"
          }
        }
      ],
      "modified": "2026-10-20T10:48:00.141328756Z",
      "provider": "osv",
      "references": [
        "https://cryptography.io/en/latest/changelog",
        "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/5R2ZOBMPWDFFHUZ6QOZZY36A6H5CGJXL/",
        "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/U23KDR2M2N7W2ZSREG63BVW7D4VC6CIZ/",
        "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WQ5G7KHKZC4SI23JE7277KZXM57GEQKT/",
        "https://github.com/pyca/cryptography/issues/3211",
        "https://github.com/pyca/cryptography/commit/b924696b2e8731f39696584d12cceeb3aeb2d874"
      ],
      "provider_metadata": {
        "unresolved_ranges": [
          {
            "cpes": [
              "cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:lts:*:*:*",
              "cpe:2.3:o:canonical:ubuntu_linux:16.10:*:*:*:*:*:*:*"
            ],
            "vendor_product": "canonical:ubuntu_linux",
            "extracted_events": [
              {
                "range": [
                  {
                    "introduced": "16.04"
                  },
                  {
                    "last_affected": "16.04"
                  },
                  {
                    "introduced": "16.10"
                  },
                  {
                    "last_affected": "16.10"
                  }
                ],
                "source": "CPE_STRING"
              }
            ]
          },
          {
            "cpes": [
              "cpe:2.3:o:fedoraproject:fedora:23:*:*:*:*:*:*:*",
              "cpe:2.3:o:fedoraproject:fedora:24:*:*:*:*:*:*:*",
              "cpe:2.3:o:fedoraproject:fedora:25:*:*:*:*:*:*:*"
            ],
            "vendor_product": "fedoraproject:fedora",
            "extracted_events": [
              {
                "range": [
                  {
                    "introduced": "23"
                  },
                  {
                    "last_affected": "23"
                  },
                  {
                    "introduced": "24"
                  },
                  {
                    "last_affected": "24"
                  },
                  {
                    "introduced": "25"
                  },
                  {
                    "last_affected": "25"
                  }
                ],
                "source": "CPE_STRING"
              }
            ]
          }
        ]
      }
    },
    "related_cves": [
      {
        "value": "CVE-2016-9243",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 379919,
  "published_at": "2017-03-27T17:59:00.46+00:00"
}