ntp: drop packets with source address ::1
Published Oct 4, 2015
6.8
MEDIUMCVSS 2.0
EPSS 4.53%
Description
The read_network_packet function in ntp_io.c in ntpd in NTP 4.x before 4.2.8p1 on Linux and OS X does not properly determine whether a source IP address is an IPv6 loopback address, which makes it easier for remote attackers to spoof restricted packets, and read or write to the runtime state, by leveraging the ability to reach the ntpd machine's network interface with a packet from the ::1 address.
Affected products
No data.
Configuration 1
Configuration 2
- 6.0
- 6.0
- 6.0
Configuration 3
- 7.0
- 8.0
- 9.0
No data.
Red Hat Enterprise Linux 6
ntp-0:4.2.6p5-5.el6
Fixed · RHSA-2015:1459
Red Hat Enterprise Linux 7
ntp-0:4.2.6p5-22.el7
Fixed · RHSA-2015:2231
Red Hat Enterprise Linux 5
ntp
Will not fix
| Product | Package | State | Advisory |
|---|---|---|---|
| Red Hat Enterprise Linux 6 | ntp-0:4.2.6p5-5.el6 | Fixed | RHSA-2015:1459 |
| Red Hat Enterprise Linux 7 | ntp-0:4.2.6p5-22.el7 | Fixed | RHSA-2015:2231 |
| Red Hat Enterprise Linux 5 | ntp | Will not fix | n/a |
No package ranges for this CVE.
Remediation
Red Hat statement
This issue affects the versions of ntp as shipped with Red Hat Enterprise Linux 5. Red Hat Enterprise Linux 5 is now in Production 3 Phase of the support and maintenance life cycle. This has been rated as having Moderate security impact and is not currently planned to be addressed in future updates. For additional information, refer to the Red Hat Enterprise Linux Life Cycle: https://access.redhat.com/support/policy/updates/errata/. To mitigate this issue, you may use the ip6tables command to prevent spoofing of local addresses on any network interface other than the loopback interface. Refer to the Mitigation section on our KBase article: https://access.redhat.com/articles/1305723
Metrics
No CVSS v4.0 score for this CVE.
No CVSS v3.1 score for this CVE.
No CVSS v3.0 score for this CVE.
AV:N/AC:M/Au:N/C:P/I:P/A:P
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 (17 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 1, 2026 | 4.53% (0.04532) | 91.25th | v5 (v2026.06.15) |
| Jun 15, 2026 | 4.53% (0.04532) | 90.30th | v5 (v2026.06.15) |
| Jan 10, 2026 | 4.84% (0.04839) | 89.20th | v4 (v2025.03.14) |
| Dec 28, 2025 | 5.98% (0.05983) | 90.36th | v4 (v2025.03.14) |
| Dec 27, 2025 | 9.65% (0.09651) | 92.67th | v4 (v2025.03.14) |
| Dec 13, 2025 | 5.96% (0.05965) | 90.31th | v4 (v2025.03.14) |
| Jun 21, 2025 | 9.65% (0.09651) | 92.51th | v4 (v2025.03.14) |
| Mar 30, 2025 | 6.49% (0.06487) | 90.17th | v4 (v2025.03.14) |
| Mar 29, 2025 | 15.02% (0.15025) | 90.98th | v4 (v2025.03.14) |
| Mar 17, 2025 | 6.49% (0.06487) | 90.40th | v4 (v2025.03.14) |
| Dec 12, 2024 | 1.42% (0.01415) | 87.03th | v3 (v2023.03.01) |
| Jul 27, 2023 | 1.42% (0.01415) | 84.74th | v3 (v2023.03.01) |
| May 22, 2023 | 1.22% (0.01224) | 83.33th | v3 (v2023.03.01) |
| Mar 7, 2023 | 0.88% (0.00882) | 80.03th | v3 (v2023.03.01) |
| Mar 6, 2023 | 1.97% (0.01974) | 78.97th | v2 (v2022.01.01) |
| Apr 1, 2022 | 1.97% (0.01974) | 77.12th | v2 (v2022.01.01) |
| Feb 4, 2022 | 1.97% (0.01974) | 56.20th | v2 (v2022.01.01) |
References (13)
- http://bugs.ntp.org/show_bug.cgi?id=2672 x_refsource_CONFIRMIssue TrackingPatchVendor Advisory
- http://rhn.redhat.com/errata/RHSA-2015-1459.html vendor-advisoryx_refsource_REDHATThird Party Advisory
- http://support.ntp.org/bin/view/Main/SecurityNotice#1_can_be_spoofed_on_some_OSes_so
- http://support.ntp.org/bin/view/Main/SecurityNotice#December_2014_NTP_Security_Vulne x_refsource_CONFIRMVendor Advisory
- http://www.debian.org/security/2015/dsa-3388 vendor-advisoryx_refsource_DEBIANThird Party Advisory
- http://www.kb.cert.org/vuls/id/852879 third-party-advisoryx_refsource_CERT-VNThird Party AdvisoryUS Government Resource
- http://www.oracle.com/technetwork/topics/security/linuxbulletinoct2015-2719645.html x_refsource_CONFIRMThird Party Advisory
- http://www.securityfocus.com/bid/72584 vdb-entryx_refsource_BIDThird Party AdvisoryVDB Entry
- https://access.redhat.com/security/cve/CVE-2014-9751 Vendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=1184572 x_refsource_CONFIRMIssue TrackingThird Party Advisory
- https://nvd.nist.gov/vuln/detail/CVE-2014-9751
- https://support.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbhf03886en_us x_refsource_CONFIRMThird Party Advisory
- https://www.cve.org/CVERecord?id=CVE-2014-9751
Change history (0)
No recorded changes yet.