{"cve":"CVE-2016-9243","nvd":{"published":"2017-03-27T17:59:00.460","modified":"2026-06-17T00:55:43.337","status":"Modified","description":"HKDF in cryptography before 1.5.2 returns an empty byte-string if used with a length less than algorithm.digest_size.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","score":7.5},"cwes":[],"references":["http://www.openwall.com/lists/oss-security/2016/11/09/2","http://www.securityfocus.com/bid/94216","http://www.ubuntu.com/usn/USN-3138-1","https://cryptography.io/en/latest/changelog","https://github.com/pyca/cryptography/commit/b924696b2e8731f39696584d12cceeb3aeb2d874"],"products":["canonical:ubuntu_linux","cryptography.io:cryptography","fedoraproject:fedora"],"source":"nvd","synced_at":"2026-10-19T20:42:09.859288039+00:00"},"epss":{"cve":"CVE-2016-9243","score":0.03464,"percentile":0.89056,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-q3cj-2r34-2cwc","url":"https://osv.dev/vulnerability/GHSA-q3cj-2r34-2cwc","summary":"Improper input validation in cryptography","modified":"2024-09-13T20:24:39.475398Z","packages":[{"ecosystem":"PyPI","name":"cryptography","purl":"pkg:pypi/cryptography","ranges":["<1.5.3"],"fixed":["1.5.3"]}]},{"id":"PYSEC-2017-8","url":"https://osv.dev/vulnerability/PYSEC-2017-8","summary":"","modified":"2023-11-08T03:58:38.234221Z","packages":[{"ecosystem":"PyPI","name":"cryptography","purl":"pkg:pypi/cryptography","ranges":["<1.5.3"],"fixed":["1.5.3"]}]}],"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."]}