{"id":"CVE-2016-4956","url":"https://www.cyber-defence.io/tools/cve/CVE-2016-4956","generatedAt":"2026-11-05T05:27:52.800Z","title":"ntpd in NTP 4.x before 4.2.8p8 allows remote attackers to cause a denial of service (interleaved-mode transition and time change) via a spoofed broadcast packet.","description":"ntpd in NTP 4.x before 4.2.8p8 allows remote attackers to cause a denial of service (interleaved-mode transition and time change) via a spoofed broadcast packet.  NOTE: this vulnerability exists because of an incomplete fix for CVE-2016-1548.","published":"2016-07-05T01:59:03.000Z","lastModified":"2026-06-17T00:48:30.000Z","status":"Modified","sourceIdentifier":"cve@mitre.org","cvss":{"version":"3.1","score":5.3,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"},"cwe":[],"affected":["ntp/ntp","oracle/solaris","suse/manager proxy","suse/openstack cloud","novell/suse manager","opensuse/leap","opensuse/opensuse","suse/linux enterprise desktop","suse/linux enterprise server","siemens/simatic net cp 443-1 opc ua firmware"],"epss":{"score":0.16351,"percentile":0.96973,"date":"2026-11-04","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"urgent","text":"EPSS puts the probability of exploitation in the next 30 days at 16.4%, higher than 97% of all known CVEs. Patch or mitigate before the next change window."},"changes":[],"references":[{"url":"http://bugs.ntp.org/3042","tags":["Issue Tracking","Vendor Advisory"],"source":"cve@mitre.org"},{"url":"http://lists.opensuse.org/opensuse-security-announce/2016-06/msg00018.html","tags":["Mailing List","Third Party Advisory"],"source":"cve@mitre.org"},{"url":"http://lists.opensuse.org/opensuse-security-announce/2016-06/msg00020.html","source":"cve@mitre.org"},{"url":"http://lists.opensuse.org/opensuse-security-announce/2016-06/msg00023.html","tags":["Mailing List","Third Party Advisory"],"source":"cve@mitre.org"},{"url":"http://lists.opensuse.org/opensuse-security-announce/2016-06/msg00024.html","tags":["Mailing List","Third Party Advisory"],"source":"cve@mitre.org"},{"url":"http://lists.opensuse.org/opensuse-security-announce/2016-06/msg00028.html","tags":["Mailing List","Third Party 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Resource"],"source":"cve@mitre.org"},{"url":"http://www.oracle.com/technetwork/topics/security/bulletinapr2016-2952098.html","tags":["Third Party Advisory"],"source":"cve@mitre.org"},{"url":"http://www.securityfocus.com/archive/1/538599/100/0/threaded","source":"cve@mitre.org"},{"url":"http://www.securityfocus.com/archive/1/538600/100/0/threaded","source":"cve@mitre.org"},{"url":"http://www.securityfocus.com/archive/1/540683/100/0/threaded","source":"cve@mitre.org"},{"url":"http://www.securityfocus.com/archive/1/archive/1/538599/100/0/threaded","source":"cve@mitre.org"},{"url":"http://www.securityfocus.com/archive/1/archive/1/538600/100/0/threaded","source":"cve@mitre.org"},{"url":"http://www.securityfocus.com/archive/1/archive/1/540683/100/0/threaded","source":"cve@mitre.org"},{"url":"http://www.securityfocus.com/bid/91009","tags":["Third Party Advisory","VDB Entry"],"source":"cve@mitre.org"},{"url":"http://www.securitytracker.com/id/1036037","tags":["Third Party Advisory","VDB Entry"],"source":"cve@mitre.org"},{"url":"http://www.ubuntu.com/usn/USN-3096-1","source":"cve@mitre.org"},{"url":"https://cert-portal.siemens.com/productcert/pdf/ssa-211752.pdf","tags":["Third Party Advisory"],"source":"cve@mitre.org"},{"url":"https://h20566.www2.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbhf03757en_us","tags":["Third Party Advisory"],"source":"cve@mitre.org"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/K3EYJQHJZ2KTVQ7ICEFHXTLZ36MRASWX/","source":"cve@mitre.org"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ORAMN3Q7TVJ54MBYF75XCJOE3DP7LYHT/","source":"cve@mitre.org"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WNWGCQLW2VY72NIUYMJOCAKJKTXHDUK2/","source":"cve@mitre.org"},{"url":"https://security.FreeBSD.org/advisories/FreeBSD-SA-16:24.ntp.asc","tags":["Third Party 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Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://lists.opensuse.org/opensuse-security-announce/2016-06/msg00024.html","tags":["Mailing List","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://lists.opensuse.org/opensuse-security-announce/2016-06/msg00028.html","tags":["Mailing List","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://lists.opensuse.org/opensuse-security-announce/2016-06/msg00040.html","tags":["Mailing List","Third Party 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Entry"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.securitytracker.com/id/1036037","tags":["Third Party Advisory","VDB Entry"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.ubuntu.com/usn/USN-3096-1","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://cert-portal.siemens.com/productcert/pdf/ssa-211752.pdf","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://h20566.www2.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbhf03757en_us","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/K3EYJQHJZ2KTVQ7ICEFHXTLZ36MRASWX/","source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2016-4956","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}