{"id":"CVE-2016-9243","aliases":["BELL-CVE-2016-9243","DEBIAN-CVE-2016-9243","EUVD-2017-0020","GHSA-q3cj-2r34-2cwc","MGASA-2016-0377","PYSEC-2017-8","UBUNTU-CVE-2016-9243","USN-3138-1"],"status":"published","title":"Improper input validation in cryptography","description":"HKDF in cryptography before 1.5.2 returns an empty byte-string if used with a length less than 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in cryptography before 1.5.2 returns an empty byte-string if used with a length less than algorithm.digest_size.","status":"published","published":"2017-03-27T17:00:00Z","modified":"2024-08-06T02:42:11.253Z","updated_at":"2026-11-02T14:33:32.415289Z"}],"euvd":[{"id":"EUVD-2017-0020","description":"HKDF in cryptography before 1.5.2 returns an empty byte-string if used with a length less than algorithm.digest_size.","status":"published","published":"2017-03-27T17:00:00Z","modified":"2024-08-06T02:42:11Z","updated_at":"2026-11-03T02:22:27.654814Z"}],"ghsa":[{"id":"GHSA-q3cj-2r34-2cwc","title":"Improper input validation in cryptography","description":"HKDF in cryptography before 1.5.3 returns an empty byte-string if used with a length less than algorithm.digest_size.","status":"published","published":"2022-05-17T02:51:56Z","modified":"2024-09-13T20:08:28Z","cvss":[{"version":"4.0","score":8.7,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N","level":"high"},{"version":"3.0","score":7.5,"vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","level":"high"}],"cwes":["CWE-20"],"updated_at":"2026-11-02T14:38:02.773864Z"}],"nvd":[{"id":"CVE-2016-9243","description":"HKDF in cryptography before 1.5.2 returns an empty byte-string if used with a length less than algorithm.digest_size.","status":"published","published":"2017-03-27T17:59:00.46Z","modified":"2026-06-17T00:55:43.337Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","level":"high","assessor":"primary"},{"version":"2.0","score":5,"vector":"AV:N/AC:L/Au:N/C:N/I:P/A:N","level":"medium","assessor":"primary"}],"updated_at":"2026-11-02T14:03:37.238712Z"}],"osv":[{"id":"BELL-CVE-2016-9243","title":"CVE-2016-9243 does not affect BellSoft software","status":"withdrawn","published":"2017-03-27T17:59:00Z","modified":"2026-01-26T09:49:37.674899Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","level":"high"}],"updated_at":"2026-11-02T15:28:14.137943Z"},{"id":"CVE-2016-9243","description":"HKDF in cryptography before 1.5.2 returns an empty byte-string if used with a length less than algorithm.digest_size.","status":"published","published":"2017-03-27T17:59:00.46Z","modified":"2026-10-20T10:48:00.141328756Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","level":"high"}],"updated_at":"2026-11-02T15:44:03.171316Z"},{"id":"DEBIAN-CVE-2016-9243","description":"HKDF in cryptography before 1.5.2 returns an empty byte-string if used with a length less than algorithm.digest_size.","status":"published","published":"2017-03-27T17:59:00.46Z","modified":"2026-09-22T07:02:38.862158153Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","level":"high"}],"updated_at":"2026-11-02T15:45:28.207321Z"},{"id":"GHSA-q3cj-2r34-2cwc","title":"Improper input validation in cryptography","description":"HKDF in cryptography before 1.5.3 returns an empty byte-string if used with a length less than 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fixes security vulnerability","description":"Fixed a bug where HKDF would return an empty byte-string if used with a\nlength less than algorithm.digest_size. (CVE-2016-9243)\n","status":"published","published":"2016-11-14T07:08:50Z","modified":"2026-04-16T06:24:37.129222239Z","updated_at":"2026-11-02T15:49:40.103088Z"},{"id":"PYSEC-2017-8","description":"HKDF in cryptography before 1.5.2 returns an empty byte-string if used with a length less than algorithm.digest_size.","status":"published","published":"2017-03-27T17:59:00Z","modified":"2023-11-08T03:58:38.234221Z","updated_at":"2026-11-02T15:52:51.645172Z"},{"id":"USN-3138-1","title":"python-cryptography vulnerability","description":"Markus Döring discovered that python-cryptography incorrectly handled\ncertain HKDF lengths. This could result in python-cryptography returning an\nempty string instead of the expected derived key.\n","status":"published","published":"2016-11-28T19:31:42Z","modified":"2026-02-10T04:41:03Z","updated_at":"2026-11-02T16:58:10.303275Z"}]}}