{"cve":"CVE-2016-9015","nvd":{"published":"2017-01-11T16:59:00.347","modified":"2026-06-17T00:55:17.957","status":"Modified","description":"Versions 1.17 and 1.18 of the Python urllib3 library suffer from a vulnerability that can cause them, in certain configurations, to not correctly validate TLS certificates. This places users of the library with those configurations at risk of man-in-the-middle and information leakage attacks. This vulnerability affects users using versions 1.17 and 1.18 of the urllib3 library, who are using the optional PyOpenSSL support for TLS instead of the regular standard library TLS backend, and who are using OpenSSL 1.1.0 via PyOpenSSL. This is an extremely uncommon configuration, so the security impact of this vulnerability is low.","cvss_v4":null,"cvss_v3":{"version":"3.0","vector":"CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N","score":3.7},"cwes":["CWE-295"],"references":["http://www.openwall.com/lists/oss-security/2016/10/27/6","http://www.securityfocus.com/bid/93941","http://www.openwall.com/lists/oss-security/2016/10/27/6","http://www.securityfocus.com/bid/93941"],"products":["python:urllib3"],"source":"nvd","synced_at":"2026-10-19T20:41:25.729257544+00:00"},"epss":{"cve":"CVE-2016-9015","score":0.00754,"percentile":0.55093,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-v4w5-p2hg-8fh6","url":"https://osv.dev/vulnerability/GHSA-v4w5-p2hg-8fh6","summary":"Urllib3 Incorrect Certificate Validation","modified":"2024-11-18T23:23:42.457541Z","packages":[{"ecosystem":"PyPI","name":"urllib3","purl":"pkg:pypi/urllib3","ranges":[">=1.17 <1.18.1"],"fixed":["1.18.1"]}]},{"id":"PYSEC-2017-98","url":"https://osv.dev/vulnerability/PYSEC-2017-98","summary":"","modified":"2026-06-10T17:02:48.350726400Z","packages":[{"ecosystem":"PyPI","name":"urllib3","purl":"pkg:pypi/urllib3","ranges":[">=1.17 <1.18.1"],"fixed":["1.18.1"]}]}],"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."]}