{"cve":"CVE-2016-5117","nvd":{"published":"2017-01-31T19:59:00.230","modified":"2026-06-17T00:48:47.210","status":"Modified","description":"OpenNTPD before 6.0p1 does not validate the CN for HTTPS constraint requests, which allows remote attackers to bypass the man-in-the-middle mitigations via a crafted timestamp constraint with a valid certificate.","cvss_v4":null,"cvss_v3":{"version":"3.0","vector":"CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N","score":5.9},"cwes":["CWE-254"],"references":["http://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.sbin/ntpd/constraint.c.diff?r1=1.27&r2=1.28","http://www.openntpd.org/txt/release-6.0p1.txt","http://www.openwall.com/lists/oss-security/2016/05/23/2","http://www.openwall.com/lists/oss-security/2016/05/29/6","http://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.sbin/ntpd/constraint.c.diff?r1=1.27&r2=1.28"],"products":["openntpd:openntpd"],"source":"nvd","synced_at":"2026-10-19T20:41:25.729257544+00:00"},"epss":{"cve":"CVE-2016-5117","score":0.00702,"percentile":0.53271,"date":"2026-10-31"},"kev":null,"osv":[],"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."]}