CVE & CISA-KEV CatalogNVD
CVE-2016-4956
MEDIUMEPSS 96th pctl5.3
CVSS v3
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.
CVSS v3 Vector
Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityNone
IntegrityNone
AvailabilityLow
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Exploit Intelligence
16.05%probability of exploitation in 30 days
96thpercentile
Very high risk: more likely to be exploited than 96% of all known CVEs.
References
- http://bugs.ntp.org/3042
- http://lists.opensuse.org/opensuse-security-announce/2016-06/msg00018.html
- http://lists.opensuse.org/opensuse-security-announce/2016-06/msg00020.html
- http://lists.opensuse.org/opensuse-security-announce/2016-06/msg00023.html
- http://lists.opensuse.org/opensuse-security-announce/2016-06/msg00024.html
- http://lists.opensuse.org/opensuse-security-announce/2016-06/msg00028.html
- http://lists.opensuse.org/opensuse-security-announce/2016-06/msg00040.html
- http://lists.opensuse.org/opensuse-security-announce/2016-07/msg00026.html
- http://lists.opensuse.org/opensuse-security-announce/2016-08/msg00042.html
- http://packetstormsecurity.com/files/137321/Slackware-Security-Advisory-ntp-Updates.html
- http://support.ntp.org/bin/view/Main/NtpBug3042
- http://support.ntp.org/bin/view/Main/SecurityNotice
- http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20160603-ntpd
- http://www.kb.cert.org/vuls/id/321640
- http://www.oracle.com/technetwork/topics/security/bulletinapr2016-2952098.html
- http://www.securityfocus.com/archive/1/538599/100/0/threaded
- http://www.securityfocus.com/archive/1/538600/100/0/threaded
- http://www.securityfocus.com/archive/1/540683/100/0/threaded
- http://www.securityfocus.com/archive/1/archive/1/538599/100/0/threaded
- http://www.securityfocus.com/archive/1/archive/1/538600/100/0/threaded
- http://www.securityfocus.com/archive/1/archive/1/540683/100/0/threaded
- http://www.securityfocus.com/bid/91009
- http://www.securitytracker.com/id/1036037
- http://www.ubuntu.com/usn/USN-3096-1
- https://cert-portal.siemens.com/productcert/pdf/ssa-211752.pdf
- https://h20566.www2.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbhf03757en_us
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/K3EYJQHJZ2KTVQ7ICEFHXTLZ36MRASWX/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ORAMN3Q7TVJ54MBYF75XCJOE3DP7LYHT/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WNWGCQLW2VY72NIUYMJOCAKJKTXHDUK2/
- https://security.FreeBSD.org/advisories/FreeBSD-SA-16:24.ntp.asc
- https://security.gentoo.org/glsa/201607-15
- https://us-cert.cisa.gov/ics/advisories/icsa-21-159-11
- https://www.kb.cert.org/vuls/id/321640
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Start freeThis product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-05-06.