Vulnerability Report

CVE-2016-4956

Title: Suse Openstack Cloud Denial of Service (DoS)

DoS

Proof Of Concept

No public PoC currently indexed for CVE-2016-4956.

CWE Category NVD-CWE-noinfo

Published Date Jul 05, 2016

Modified Date May 06, 2026

Exploit Status Not Found

Score 5.3 CVSS v3.1

Exploit Probability (EPSS)

1.42%

Vulnerability Summary

CVE-2016-4956: 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.

Impacted Vendors

Reference Links

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 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

CVSS v3.1

Source Entity [email protected]

Severity MEDIUM

5.3

Attack Vector

NETWORK

Complexity

LOW

Privileges

N/A

Interaction

NONE

Confidentiality

N/A

Integrity

N/A

Availability

N/A

Scope

UNCHANGED

RAW VECTOR CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

CVSS v2.0

Source Entity [email protected]

Severity MEDIUM

5.0

Access Vector

N/A

Authentication

N/A

RAW VECTOR AV:N/AC:L/Au:N/C:N/I:N/A:P

Associated Attack Patterns (CAPEC)

Total: Patterns

CVE-2016-4956 Exploits & PoCs (Proof Of Concept)

No public PoCs found in our database for this CVE.

May 06, 2026 MODIFIED

Vulnerability data updated via NVD.

April 12, 2025 MODIFIED

Vulnerability data or affected products updated.

July 05, 2016 PUBLISHED

Vulnerability first announced in NVD.

Attack Vector Matrix

Access Vector NETWORK

Complexity LOW

Privileges N/A

Interaction NONE

CVSS Vector String


                                    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Affected Stack

No specific products linked.