MEDIUM
ntp: assertion failure in ntpd on duplicate IPs on unconfig directives
Published Jan 30, 2017
5.3
MEDIUMCVSS 3.0
EPSS 8.95%
Description
NTP before 4.2.8p7 and 4.3.x before 4.3.92, when mode7 is enabled, allows remote attackers to cause a denial of service (ntpd abort) by using the same IP address multiple times in an unconfig directive.
Affected products
No data.
Configuration 2
OR
- 4.3.0
- 4.3.1
- 4.3.2
- 4.3.3
- 4.3.4
- 4.3.5
- 4.3.6
- 4.3.7
- 4.3.8
- 4.3.9
- 4.3.10
- 4.3.11
- 4.3.12
- 4.3.13
- 4.3.14
- 4.3.15
- 4.3.16
- 4.3.17
- 4.3.18
- 4.3.19
- 4.3.20
- 4.3.21
- 4.3.22
- 4.3.23
- 4.3.24
- 4.3.25
- 4.3.26
- 4.3.27
- 4.3.28
- 4.3.29
- 4.3.30
- 4.3.31
- 4.3.32
- 4.3.33
- 4.3.34
- 4.3.35
- 4.3.36
- 4.3.37
- 4.3.38
- 4.3.39
- 4.3.40
- 4.3.41
- 4.3.42
- 4.3.43
- 4.3.44
- 4.3.45
- 4.3.46
- 4.3.47
- 4.3.48
- 4.3.49
- 4.3.50
- 4.3.51
- 4.3.52
- 4.3.53
- 4.3.54
- 4.3.55
- 4.3.56
- 4.3.57
- 4.3.58
- 4.3.59
- 4.3.60
- 4.3.61
- 4.3.62
- 4.3.63
- 4.3.64
- 4.3.65
- 4.3.66
- 4.3.67
- 4.3.68
- 4.3.69
- 4.3.70
- 4.3.71
- 4.3.72
- 4.3.73
- 4.3.74
- 4.3.75
- 4.3.76
- 4.3.77
- 4.3.78
- 4.3.79
- 4.3.80
- 4.3.81
- 4.3.82
- 4.3.83
- 4.3.84
- 4.3.85
- 4.3.86
- 4.3.87
- 4.3.88
- 4.3.89
- 4.3.90
- 4.3.91
No data.
Red Hat Enterprise Linux 5
ntp
Not affected
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 | Not affected | 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
Disable remote configuration of NTP, or restrict this ability to trusted users.
Metrics
No CVSS v4.0 score for this CVE.
No CVSS v3.1 score for this CVE.
5.3 MEDIUM NVD
CVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
Attack Vector Network
Attack Complexity High
Privileges Required Low
User Interaction None
Scope Unchanged
Confidentiality Impact None
Integrity Impact None
Availability Impact High
7.1 HIGH NVD
AV:N/AC:M/Au:N/C:N/I:N/A:C
Access Vector Network
Access Complexity Medium
Authentication None
Confidentiality Impact None
Integrity Impact None
Availability Impact Complete
This CVE is not in the KEV list.
No CISA SSVC assessment for this CVE yet.
8.95% 0.08948
Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 1, 2026.
EPSS probability 0.08948
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 (32 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 1, 2026 | 8.95% (0.08948) | 95.10th | v5 (v2026.06.15) |
| Sep 22, 2026 | 8.95% (0.08948) | 95.01th | v5 (v2026.06.15) |
| Sep 21, 2026 | 11.41% (0.11413) | 95.86th | v5 (v2026.06.15) |
| Sep 6, 2026 | 8.95% (0.08948) | 94.90th | v5 (v2026.06.15) |
| Sep 5, 2026 | 11.41% (0.11413) | 95.77th | v5 (v2026.06.15) |
| Aug 30, 2026 | 8.95% (0.08948) | 94.87th | v5 (v2026.06.15) |
| Aug 28, 2026 | 11.41% (0.11413) | 95.75th | v5 (v2026.06.15) |
| Aug 24, 2026 | 8.95% (0.08948) | 94.84th | v5 (v2026.06.15) |
| Aug 23, 2026 | 11.41% (0.11413) | 95.74th | v5 (v2026.06.15) |
| Jun 15, 2026 | 8.98% (0.08980) | 94.58th | v5 (v2026.06.15) |
| Feb 18, 2026 | 3.65% (0.03648) | 87.59th | v4 (v2025.03.14) |
| Jan 18, 2026 | 14.65% (0.14650) | 94.27th | v4 (v2025.03.14) |
| Jan 14, 2026 | 12.55% (0.12550) | 93.72th | v4 (v2025.03.14) |
| Dec 28, 2025 | 14.65% (0.14650) | 94.25th | v4 (v2025.03.14) |
| Dec 27, 2025 | 17.86% (0.17861) | 94.94th | v4 (v2025.03.14) |
| Dec 20, 2025 | 14.65% (0.14650) | 94.24th | v4 (v2025.03.14) |
| Dec 15, 2025 | 18.68% (0.18681) | 95.04th | v4 (v2025.03.14) |
| Dec 13, 2025 | 20.44% (0.20441) | 95.34th | v4 (v2025.03.14) |
| Aug 10, 2025 | 17.86% (0.17861) | 94.85th | v4 (v2025.03.14) |
| Jul 28, 2025 | 23.36% (0.23364) | 95.70th | v4 (v2025.03.14) |
| Jun 19, 2025 | 19.53% (0.19525) | 95.08th | v4 (v2025.03.14) |
| Mar 30, 2025 | 23.36% (0.23364) | 95.49th | v4 (v2025.03.14) |
| Mar 29, 2025 | 34.82% (0.34820) | 95.39th | v4 (v2025.03.14) |
| Mar 17, 2025 | 23.36% (0.23364) | 95.50th | v4 (v2025.03.14) |
| Dec 12, 2024 | 2.51% (0.02512) | 90.53th | v3 (v2023.03.01) |
| Jan 3, 2024 | 1.79% (0.01787) | 86.73th | v3 (v2023.03.01) |
| Nov 21, 2023 | 1.73% (0.01731) | 86.45th | v3 (v2023.03.01) |
| Mar 7, 2023 | 1.55% (0.01548) | 85.07th | v3 (v2023.03.01) |
| Mar 6, 2023 | 1.65% (0.01649) | 75.99th | v2 (v2022.01.01) |
| Feb 23, 2023 | 1.65% (0.01649) | 75.95th | v2 (v2022.01.01) |
| Apr 1, 2022 | 1.65% (0.01649) | 73.90th | v2 (v2022.01.01) |
| Feb 4, 2022 | 1.65% (0.01649) | 52.77th | v2 (v2022.01.01) |
Weaknesses (1)
References (14)
- http://support.ntp.org/bin/view/Main/NtpBug3011 x_refsource_CONFIRMVendor Advisory
- http://support.ntp.org/bin/view/Main/SecurityNotice#April_2016_NTP_4_2_8p7_Security
- http://www.debian.org/security/2016/dsa-3629 vendor-advisoryx_refsource_DEBIAN
- http://www.oracle.com/technetwork/topics/security/bulletinapr2016-2952098.html x_refsource_CONFIRMThird Party Advisory
- http://www.securityfocus.com/bid/88180 vdb-entryx_refsource_BIDThird Party AdvisoryVDB Entry
- http://www.securitytracker.com/id/1035705 vdb-entryx_refsource_SECTRACK
- https://access.redhat.com/security/cve/CVE-2016-2516 Vendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=1331466 Issue Tracking
- https://nvd.nist.gov/vuln/detail/CVE-2016-2516
- https://security.FreeBSD.org/advisories/FreeBSD-SA-16:16.ntp.asc vendor-advisoryx_refsource_FREEBSD
- https://security.gentoo.org/glsa/201607-15 vendor-advisoryx_refsource_GENTOO
- https://security.netapp.com/advisory/ntap-20171004-0002/ x_refsource_CONFIRM
- https://www.cve.org/CVERecord?id=CVE-2016-2516
- https://www.kb.cert.org/vuls/id/718152 third-party-advisoryx_refsource_CERT-VNThird Party AdvisoryUS Government Resource
Change history (0)
No recorded changes yet.
Sources
CVE.org / MITRE
Status PUBLISHED
Assigner mitre
Published Jan 30, 2017
Updated Aug 5, 2024
Reserved Feb 20, 2016
Link CVE-2016-2516
CISA Vulnrichment
Updated n/a