MEDIUM
ntp: broadcast interleave (incomplete fix for CVE-2016-1548)
Published Jul 5, 2016
5.3
MEDIUMCVSS 3.1
EPSS 16.35%
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.
Affected products
No data.
Configuration 1
OR
- ≥ 4.2.0 · < 4.2.8
- ≥ 4.3.0 · < 4.3.93
- 4.2.8
- 4.2.8
- 4.2.8
- 4.2.8
- 4.2.8
- 4.2.8
- 4.2.8
- 4.2.8
- 4.2.8
- 4.2.8
- 4.2.8
- 4.2.8
- 4.2.8
- 4.2.8
- 4.2.8
- 4.2.8
- 4.2.8
- 4.2.8
- 4.2.8
- 4.2.8
- 4.2.8
Configuration 3
OR
- 2.1
- 5
- 2.1
- 42.1
- 13.2
- 12
- 11
- 11
- 11
- 12
Configuration 4
AND
Running on/with
- n/a
No data.
Red Hat Enterprise Linux 5
ntp
Will not fix
Red Hat Enterprise Linux 6
ntp
Will not fix
Red Hat Enterprise Linux 7
ntp
Will not fix
| Product | Package | State | Advisory |
|---|---|---|---|
| Red Hat Enterprise Linux 5 | ntp | Will not fix | n/a |
| Red Hat Enterprise Linux 6 | ntp | Will not fix | n/a |
| Red Hat Enterprise Linux 7 | ntp | Will not fix | n/a |
No package ranges for this CVE.
Remediation
Red Hat mitigation
Do not use NTP's broadcast mode in the clients by not configuring the "broadcastclient" directive in the ntp.conf file.
Metrics
No CVSS v4.0 score for this CVE.
5.3 MEDIUM NVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction None
Scope Unchanged
Confidentiality Impact None
Integrity Impact None
Availability Impact Low
No CVSS v3.0 score for this CVE.
5.0 MEDIUM NVD
AV:N/AC:L/Au:N/C:N/I:N/A:P
Access Vector Network
Access Complexity Low
Authentication None
Confidentiality Impact None
Integrity Impact None
Availability Impact Partial
This CVE is not in the KEV list.
No CISA SSVC assessment for this CVE yet.
16.35% 0.16351
Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 1, 2026.
EPSS probability 0.16351
Score over time
2022–2026- EPSS v2
- EPSS v3
- EPSS v4
- EPSS v5
Percentile over time
- EPSS v2
- EPSS v3
- EPSS v4
- EPSS v5
Table of values (20 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 1, 2026 | 16.35% (0.16351) | 96.87th | v5 (v2026.06.15) |
| Jun 15, 2026 | 16.05% (0.16055) | 96.49th | v5 (v2026.06.15) |
| Feb 18, 2026 | 1.13% (0.01129) | 77.94th | v4 (v2025.03.14) |
| Jan 14, 2026 | 3.62% (0.03621) | 87.45th | v4 (v2025.03.14) |
| Jun 19, 2025 | 2.04% (0.02037) | 82.98th | v4 (v2025.03.14) |
| Mar 30, 2025 | 3.06% (0.03059) | 85.50th | v4 (v2025.03.14) |
| Mar 29, 2025 | 4.13% (0.04129) | 80.72th | v4 (v2025.03.14) |
| Mar 17, 2025 | 2.74% (0.02741) | 85.01th | v4 (v2025.03.14) |
| Dec 17, 2024 | 6.31% (0.06307) | 93.57th | v3 (v2023.03.01) |
| Apr 27, 2024 | 2.34% (0.02338) | 89.62th | v3 (v2023.03.01) |
| Feb 21, 2024 | 2.03% (0.02027) | 88.56th | v3 (v2023.03.01) |
| Dec 15, 2023 | 1.77% (0.01771) | 86.62th | v3 (v2023.03.01) |
| Oct 5, 2023 | 1.74% (0.01742) | 86.47th | v3 (v2023.03.01) |
| Jul 17, 2023 | 1.44% (0.01436) | 84.79th | v3 (v2023.03.01) |
| Jun 7, 2023 | 1.22% (0.01224) | 83.41th | v3 (v2023.03.01) |
| Apr 25, 2023 | 1.19% (0.01185) | 83.01th | v3 (v2023.03.01) |
| Mar 7, 2023 | 0.56% (0.00565) | 74.38th | v3 (v2023.03.01) |
| Mar 6, 2023 | 4.36% (0.04358) | 88.02th | v2 (v2022.01.01) |
| Apr 1, 2022 | 4.36% (0.04358) | 86.83th | v2 (v2022.01.01) |
| Feb 4, 2022 | 4.36% (0.04358) | 70.59th | v2 (v2022.01.01) |
Weaknesses (0)
No CWE recorded.
References (38)
- http://bugs.ntp.org/3042 x_refsource_CONFIRMIssue TrackingVendor Advisory
- http://lists.opensuse.org/opensuse-security-announce/2016-06/msg00018.html vendor-advisoryx_refsource_SUSEMailing ListThird Party Advisory
- http://lists.opensuse.org/opensuse-security-announce/2016-06/msg00020.html vendor-advisoryx_refsource_SUSE
- http://lists.opensuse.org/opensuse-security-announce/2016-06/msg00023.html vendor-advisoryx_refsource_SUSEMailing ListThird Party Advisory
- http://lists.opensuse.org/opensuse-security-announce/2016-06/msg00024.html vendor-advisoryx_refsource_SUSEMailing ListThird Party Advisory
- http://lists.opensuse.org/opensuse-security-announce/2016-06/msg00028.html vendor-advisoryx_refsource_SUSEMailing ListThird Party Advisory
- http://lists.opensuse.org/opensuse-security-announce/2016-06/msg00040.html vendor-advisoryx_refsource_SUSEMailing ListThird Party Advisory
- http://lists.opensuse.org/opensuse-security-announce/2016-07/msg00026.html vendor-advisoryx_refsource_SUSE
- http://lists.opensuse.org/opensuse-security-announce/2016-08/msg00042.html vendor-advisoryx_refsource_SUSE
- http://packetstormsecurity.com/files/137321/Slackware-Security-Advisory-ntp-Updates.html x_refsource_MISC
- http://support.ntp.org/bin/view/Main/NtpBug3042 x_refsource_CONFIRMVendor Advisory
- http://support.ntp.org/bin/view/Main/SecurityNotice x_refsource_CONFIRMRelease NotesVendor Advisory
- http://support.ntp.org/bin/view/Main/SecurityNotice#June_2016_ntp_4_2_8p8_NTP_Securi
- http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20160603-ntpd vendor-advisoryx_refsource_CISCO
- http://www.kb.cert.org/vuls/id/321640 third-party-advisoryx_refsource_CERT-VNThird Party AdvisoryUS Government Resource
- http://www.oracle.com/technetwork/topics/security/bulletinapr2016-2952098.html x_refsource_CONFIRMThird Party Advisory
- http://www.securityfocus.com/archive/1/538599/100/0/threaded mailing-listx_refsource_BUGTRAQ
- http://www.securityfocus.com/archive/1/538600/100/0/threaded mailing-listx_refsource_BUGTRAQ
- http://www.securityfocus.com/archive/1/540683/100/0/threaded mailing-listx_refsource_BUGTRAQ
- http://www.securityfocus.com/archive/1/archive/1/538599/100/0/threaded mailing-listx_refsource_BUGTRAQ
- http://www.securityfocus.com/archive/1/archive/1/538600/100/0/threaded mailing-listx_refsource_BUGTRAQ
- http://www.securityfocus.com/archive/1/archive/1/540683/100/0/threaded mailing-listx_refsource_BUGTRAQ
- http://www.securityfocus.com/bid/91009 vdb-entryx_refsource_BIDThird Party AdvisoryVDB Entry
- http://www.securitytracker.com/id/1036037 vdb-entryx_refsource_SECTRACKThird Party AdvisoryVDB Entry
- http://www.ubuntu.com/usn/USN-3096-1 vendor-advisoryx_refsource_UBUNTU
- https://access.redhat.com/security/cve/CVE-2016-4956 Vendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=1340860 Issue Tracking
- https://cert-portal.siemens.com/productcert/pdf/ssa-211752.pdf x_refsource_CONFIRMThird Party Advisory
- https://h20566.www2.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbhf03757en_us x_refsource_CONFIRMThird Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/K3EYJQHJZ2KTVQ7ICEFHXTLZ36MRASWX/ vendor-advisoryx_refsource_FEDORA
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ORAMN3Q7TVJ54MBYF75XCJOE3DP7LYHT/ vendor-advisoryx_refsource_FEDORA
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WNWGCQLW2VY72NIUYMJOCAKJKTXHDUK2/ vendor-advisoryx_refsource_FEDORA
- https://nvd.nist.gov/vuln/detail/CVE-2016-4956
- https://security.FreeBSD.org/advisories/FreeBSD-SA-16:24.ntp.asc vendor-advisoryx_refsource_FREEBSDThird Party Advisory
- https://security.gentoo.org/glsa/201607-15 vendor-advisoryx_refsource_GENTOOThird Party Advisory
- https://us-cert.cisa.gov/ics/advisories/icsa-21-159-11 x_refsource_MISC
- https://www.cve.org/CVERecord?id=CVE-2016-4956
- https://www.kb.cert.org/vuls/id/321640 third-party-advisoryx_refsource_CERT-VN
Change history (0)
No recorded changes yet.
Sources
CVE.org / MITRE
Status PUBLISHED
Assigner mitre
Published Jul 5, 2016
Updated Aug 6, 2024
Reserved May 23, 2016
Link CVE-2016-4956
CISA Vulnrichment
Updated n/a