ntp: Unauthenticated packet can reset authenticated interleaved association
Published Mar 6, 2018
7.5
HIGHCVSS 3.1
EPSS 9.00%
Description
The protocol engine in ntp 4.2.6 before 4.2.8p11 allows a remote attackers to cause a denial of service (disruption) by continually sending a packet with a zero-origin timestamp and source IP address of the "other side" of an interleaved association causing the victim ntpd to reset its association.
Affected products
No data.
Configuration 1
- ≥ 4.2.6 · < 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
- 4.2.8
- 4.2.8
- 4.2.8
- 4.2.8
Configuration 2
- ≥ 1.1 · < 1.1.6-6931-3
- < 6.1.5-15254
- < 6.1.6-15266
- ≥ 5.2 · < 6.1.6-15266
Configuration 3
- < 2.2.3-1505
Configuration 4
- 12.04
- 14.04
- 16.04
- 17.10
- 18.04
Configuration 6
- < c.4.2.8.4.0
Configuration 7
- < xcp2361
Running on/with
- n/a
Configuration 8
- < xcp2361
Running on/with
- n/a
Configuration 9
- < xcp2361
Running on/with
- n/a
Configuration 10
- < xcp2361
Running on/with
- n/a
Configuration 11
- < xcp2361
Running on/with
- n/a
Configuration 12
- < xcp2361
Running on/with
- n/a
Configuration 13
- < xcp3070
Running on/with
- n/a
Configuration 14
- < xcp3070
Running on/with
- n/a
Configuration 15
- < xcp3070
Running on/with
- n/a
Configuration 16
- < xcp3070
Running on/with
- n/a
Configuration 17
- < xcp3070
Running on/with
- n/a
Configuration 18
- < xcp3070
Running on/with
- n/a
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
Red Hat Enterprise Linux 8
ntp
Fix deferred
| 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 |
| Red Hat Enterprise Linux 8 | ntp | Fix deferred | n/a |
No package ranges for this CVE.
Remediation
Red Hat mitigation
Remove the "xleave" option from the "peer HOST xleave" lines in your ntp.conf if it exists, to entirely disable interleaved mode.
Metrics
No CVSS v4.0 score for this CVE.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L
AV:N/AC:L/Au:N/C:N/I:N/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
2021–2026- EPSS v1
- EPSS v2
- EPSS v3
- EPSS v4
- EPSS v5
Percentile over time
- EPSS v1
- EPSS v2
- EPSS v3
- EPSS v4
- EPSS v5
Table of values (31 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 1, 2026 | 9.00% (0.08998) | 95.12th | v5 (v2026.06.15) |
| Jun 15, 2026 | 9.24% (0.09239) | 94.69th | v5 (v2026.06.15) |
| Dec 19, 2025 | 3.51% (0.03506) | 87.23th | v4 (v2025.03.14) |
| Nov 21, 2025 | 4.70% (0.04699) | 88.88th | v4 (v2025.03.14) |
| Nov 18, 2025 | 16.82% (0.16820) | 94.43th | v4 (v2025.03.14) |
| Nov 17, 2025 | 4.70% (0.04699) | 88.86th | v4 (v2025.03.14) |
| Nov 9, 2025 | 9.38% (0.09378) | 92.42th | v4 (v2025.03.14) |
| Oct 28, 2025 | 13.20% (0.13196) | 93.82th | v4 (v2025.03.14) |
| Oct 27, 2025 | 9.58% (0.09579) | 92.53th | v4 (v2025.03.14) |
| Oct 22, 2025 | 13.20% (0.13196) | 93.81th | v4 (v2025.03.14) |
| Oct 1, 2025 | 16.93% (0.16925) | 94.76th | v4 (v2025.03.14) |
| Aug 10, 2025 | 12.47% (0.12469) | 93.63th | v4 (v2025.03.14) |
| Jul 30, 2025 | 8.83% (0.08834) | 92.16th | v4 (v2025.03.14) |
| Jun 19, 2025 | 11.19% (0.11185) | 93.15th | v4 (v2025.03.14) |
| Mar 30, 2025 | 15.58% (0.15581) | 94.12th | v4 (v2025.03.14) |
| Mar 29, 2025 | 13.73% (0.13734) | 90.44th | v4 (v2025.03.14) |
| Mar 17, 2025 | 15.58% (0.15581) | 94.18th | v4 (v2025.03.14) |
| Dec 25, 2024 | 14.19% (0.14195) | 95.68th | v3 (v2023.03.01) |
| Dec 17, 2024 | 12.21% (0.12211) | 95.36th | v3 (v2023.03.01) |
| Jun 9, 2024 | 3.27% (0.03268) | 91.27th | v3 (v2023.03.01) |
| May 1, 2024 | 3.22% (0.03224) | 91.11th | v3 (v2023.03.01) |
| Jul 28, 2023 | 2.88% (0.02879) | 89.37th | v3 (v2023.03.01) |
| Jul 8, 2023 | 3.74% (0.03742) | 90.52th | v3 (v2023.03.01) |
| Mar 7, 2023 | 4.24% (0.04242) | 90.93th | v3 (v2023.03.01) |
| Mar 6, 2023 | 2.17% (0.02172) | 80.77th | v2 (v2022.01.01) |
| Apr 1, 2022 | 2.17% (0.02172) | 78.91th | v2 (v2022.01.01) |
| Feb 4, 2022 | 2.17% (0.02172) | 57.73th | v2 (v2022.01.01) |
| Feb 3, 2022 | 4.14% (0.04139) | 74.02th | v1 |
| Jan 6, 2022 | 4.14% (0.04139) | 73.79th | v1 |
| Sep 1, 2021 | 4.14% (0.04139) | 83.38th | v1 |
| Apr 14, 2021 | 4.14% (0.04139) | 0.00th | v1 |
No CWE recorded.
References (16)
- http://packetstormsecurity.com/files/146631/Slackware-Security-Advisory-ntp-Updates.html x_refsource_MISCThird Party AdvisoryVDB Entry
- http://support.ntp.org/bin/view/Main/NtpBug3454 x_refsource_CONFIRMMitigationVendor Advisory
- http://www.securityfocus.com/archive/1/541824/100/0/threaded mailing-listx_refsource_BUGTRAQThird Party AdvisoryVDB Entry
- http://www.securityfocus.com/bid/103339 vdb-entryx_refsource_BIDThird Party AdvisoryVDB Entry
- https://access.redhat.com/security/cve/CVE-2018-7185 Vendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=1550220 Issue Tracking
- https://nvd.nist.gov/vuln/detail/CVE-2018-7185
- https://security.FreeBSD.org/advisories/FreeBSD-SA-18:02.ntp.asc vendor-advisoryx_refsource_FREEBSDThird Party Advisory
- https://security.gentoo.org/glsa/201805-12 vendor-advisoryx_refsource_GENTOOThird Party Advisory
- https://security.netapp.com/advisory/ntap-20180626-0001/ x_refsource_CONFIRMThird Party Advisory
- https://support.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbux03962en_us x_refsource_CONFIRMThird Party Advisory
- https://usn.ubuntu.com/3707-1/ vendor-advisoryx_refsource_UBUNTUThird Party Advisory
- https://usn.ubuntu.com/3707-2/ vendor-advisoryx_refsource_UBUNTUThird Party Advisory
- https://www.cve.org/CVERecord?id=CVE-2018-7185
- https://www.oracle.com/technetwork/security-advisory/cpuoct2019-5072832.html x_refsource_MISCThird Party Advisory
- https://www.synology.com/support/security/Synology_SA_18_13 x_refsource_CONFIRMThird Party Advisory
Change history (0)
No recorded changes yet.