ntp: certain remote configuration values not properly validated
Published Jan 30, 2017
5.3
MEDIUMCVSS 3.0
EPSS 8.82%
Description
NTP before 4.2.8p7 and 4.3.x before 4.3.92 allows remote attackers to cause a denial of service (prevent subsequent authentication) by leveraging knowledge of the controlkey or requestkey and sending a crafted packet to ntpd, which changes the value of trustedkey, controlkey, or requestkey. NOTE: this vulnerability exists because of a CVE-2016-2516 regression.
Affected products
No data.
Configuration 2
- 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
Not affected
Red Hat Enterprise Linux 7
ntp
Not affected
| Product | Package | State | Advisory |
|---|---|---|---|
| Red Hat Enterprise Linux 5 | ntp | Not affected | n/a |
| Red Hat Enterprise Linux 6 | ntp | Not affected | n/a |
| Red Hat Enterprise Linux 7 | ntp | Not affected | n/a |
No package ranges for this CVE.
Remediation
Red Hat statement
Red Hat Product Security does not consider this to be a security issue. An authenticated user could use various other means to disable access to an NTP server (for example, using the 'restrict' command). To mitigate this issue, 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.
CVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
AV:N/AC:H/Au:S/C:N/I:N/A:C
This CVE is not in the KEV list.
No CISA SSVC assessment for this CVE yet.
Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 1, 2026.
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 (28 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 1, 2026 | 8.82% (0.08823) | 95.04th | v5 (v2026.06.15) |
| Sep 22, 2026 | 8.82% (0.08823) | 94.95th | v5 (v2026.06.15) |
| Sep 21, 2026 | 7.51% (0.07505) | 94.30th | v5 (v2026.06.15) |
| Sep 6, 2026 | 8.82% (0.08823) | 94.84th | v5 (v2026.06.15) |
| Sep 5, 2026 | 7.51% (0.07505) | 94.17th | v5 (v2026.06.15) |
| Aug 30, 2026 | 8.82% (0.08823) | 94.81th | v5 (v2026.06.15) |
| Aug 28, 2026 | 7.51% (0.07505) | 94.14th | v5 (v2026.06.15) |
| Aug 24, 2026 | 8.82% (0.08823) | 94.78th | v5 (v2026.06.15) |
| Aug 23, 2026 | 7.51% (0.07505) | 94.11th | v5 (v2026.06.15) |
| Jun 15, 2026 | 8.82% (0.08823) | 94.50th | v5 (v2026.06.15) |
| Jan 18, 2026 | 3.01% (0.03007) | 86.20th | v4 (v2025.03.14) |
| Dec 28, 2025 | 7.25% (0.07249) | 91.32th | v4 (v2025.03.14) |
| Dec 27, 2025 | 9.05% (0.09054) | 92.40th | v4 (v2025.03.14) |
| Dec 20, 2025 | 7.25% (0.07249) | 91.31th | v4 (v2025.03.14) |
| Dec 15, 2025 | 9.53% (0.09528) | 92.55th | v4 (v2025.03.14) |
| Dec 13, 2025 | 10.57% (0.10566) | 93.00th | v4 (v2025.03.14) |
| Aug 10, 2025 | 9.05% (0.09054) | 92.28th | v4 (v2025.03.14) |
| Mar 30, 2025 | 4.55% (0.04549) | 88.15th | v4 (v2025.03.14) |
| Mar 29, 2025 | 8.54% (0.08544) | 87.11th | v4 (v2025.03.14) |
| Mar 17, 2025 | 3.82% (0.03820) | 87.35th | v4 (v2025.03.14) |
| Dec 12, 2024 | 0.95% (0.00955) | 83.91th | v3 (v2023.03.01) |
| Feb 15, 2024 | 0.48% (0.00476) | 75.04th | v3 (v2023.03.01) |
| Nov 21, 2023 | 0.48% (0.00476) | 73.04th | v3 (v2023.03.01) |
| Mar 7, 2023 | 0.43% (0.00425) | 70.31th | v3 (v2023.03.01) |
| Mar 6, 2023 | 1.31% (0.01315) | 68.50th | v2 (v2022.01.01) |
| Feb 22, 2023 | 1.31% (0.01315) | 68.21th | v2 (v2022.01.01) |
| Apr 1, 2022 | 1.31% (0.01315) | 66.08th | v2 (v2022.01.01) |
| Feb 4, 2022 | 1.31% (0.01315) | 41.88th | v2 (v2022.01.01) |
References (13)
- http://support.ntp.org/bin/view/Main/NtpBug3010 x_refsource_CONFIRMVendor Advisory
- http://support.ntp.org/bin/view/Main/SecurityNotice#April_2016_NTP_4_2_8p7_Security
- http://www.oracle.com/technetwork/topics/security/bulletinapr2016-2952098.html x_refsource_CONFIRMThird Party Advisory
- http://www.securityfocus.com/bid/88189 vdb-entryx_refsource_BIDThird Party AdvisoryVDB Entry
- http://www.securitytracker.com/id/1035705 vdb-entryx_refsource_SECTRACK
- https://access.redhat.com/security/cve/CVE-2016-2517 Vendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=1331467 Issue Tracking
- https://nvd.nist.gov/vuln/detail/CVE-2016-2517
- 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-2016-2517
- 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.