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CVE-2020-13817

ntpd in ntp before 4.2.8p14 and 4.3.x before 4.3.100 allows remote attackers to cause a denial of...

5.9 MediumFix available

CVE-2020-13817 is a medium vulnerability (CVSS 5.9) in Ntp, published June 4, 2020. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 3.36%, the 88th percentile. Fixed in ntp 4.2.6p5-16.el6.tuxcare.els1.

ntpd in ntp before 4.2.8p14 and 4.3.x before 4.3.100 allows remote attackers to cause a denial of service (daemon exit or system time change) by predicting transmit timestamps for use in spoofed packets. The victim must be relying on unauthenticated IPv4 time sources. There must be an off-path attacker who can query time from the victim's ntpd instance.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
High
Privileges needed
None
User interaction
None

What an attacker can affect

Confidentiality
None
Integrity
None
Availability
High

Exploit likelihood

3.36%Up 1.1 points since Apr 14, 2021
90%50%10%1%

What each source reports

CVE List 7.4

ntpd in ntp before 4.2.8p14 and 4.3.x before 4.3.100 allows remote attackers to cause a denial of service (daemon exit or system time change) by predicting transmit timestamps for use in spoofed packets. The victim must be relying on unauthenticated IPv4 time sources. There must be an off-path attacker who can query time from the victim's ntpd instance.

Record
CVE-2020-13817
CVSS 3.1
7.4 HighCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:H
CVSS 3.0
5.9 MediumCVSS:3.0/AC:H/AV:N/A:H/C:N/I:N/PR:N/S:U/UI:N
Weakness
CWE-330
Updated
2026-11-02
EUVDEUVD-2020-6032 7.4

ntpd in ntp before 4.2.8p14 and 4.3.x before 4.3.100 allows remote attackers to cause a denial of service (daemon exit or system time change) by predicting transmit timestamps for use in spoofed packets. The victim must be relying on unauthenticated IPv4 time sources. There must be an off-path attacker who can query time from the victim's ntpd instance.

Record
EUVD-2020-6032
CVSS 3.1
7.4 HighCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:H
Updated
2026-11-02
GitHub AdvisoriesGHSA-fx6x-7xgx-2wwp 7.4

ntpd in ntp before 4.2.8p14 and 4.3.x before 4.3.100 allows remote attackers to cause a denial of...

ntpd in ntp before 4.2.8p14 and 4.3.x before 4.3.100 allows remote attackers to cause a denial of service (daemon exit or system time change) by predicting transmit timestamps for use in spoofed packets. The victim must be relying on unauthenticated IPv4 time sources. There must be an off-path attacker who can query time from the victim's ntpd instance.

Record
GHSA-fx6x-7xgx-2wwp
CVSS 3.1
7.4 HighCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:H
Weakness
CWE-20, CWE-330
Updated
2026-11-02
NVD 7.4

ntpd in ntp before 4.2.8p14 and 4.3.x before 4.3.100 allows remote attackers to cause a denial of service (daemon exit or system time change) by predicting transmit timestamps for use in spoofed packets. The victim must be relying on unauthenticated IPv4 time sources. There must be an off-path attacker who can query time from the victim's ntpd instance.

Record
CVE-2020-13817
CVSS 3.1
7.4 HighCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:H
CVSS 3.0
5.9 MediumCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS 2.0
5.8 MediumAV:N/AC:M/Au:N/C:N/I:P/A:P
Weakness
CWE-330
Updated
2026-11-02
OSV 7.4

ntpd in ntp before 4.2.8p14 and 4.3.x before 4.3.100 allows remote attackers to cause a denial of service (daemon exit or system time change) by predicting transmit timestamps for use in spoofed packets. The victim must be relying on unauthenticated IPv4 time sources. There must be an off-path attacker who can query time from the victim's ntpd instance.

Record
CVE-2020-13817
CVSS 3.1
7.4 HighCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:H
Updated
2026-11-02
OSVDEBIAN-CVE-2020-13817 7.4

ntpd in ntp before 4.2.8p14 and 4.3.x before 4.3.100 allows remote attackers to cause a denial of service (daemon exit or system time change) by predicting transmit timestamps for use in spoofed packets. The victim must be relying on unauthenticated IPv4 time sources. There must be an off-path attacker who can query time from the victim's ntpd instance.

Record
DEBIAN-CVE-2020-13817
CVSS 3.1
7.4 HighCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:H
Updated
2026-11-02
Show 10 moreShow less
OSVRHSA-2020:2663 7.4

Red Hat Security Advisory: ntp security update

Record
RHSA-2020:2663
CVSS 3.1
7.4 HighCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:H
Updated
2026-11-02
OSVUBUNTU-CVE-2020-13817 7.4

ntpd in ntp before 4.2.8p14 and 4.3.x before 4.3.100 allows remote attackers to cause a denial of service (daemon exit or system time change) by predicting transmit timestamps for use in spoofed packets. The victim must be relying on unauthenticated IPv4 time sources. There must be an off-path attacker who can query time from the victim's ntpd instance.

Record
UBUNTU-CVE-2020-13817
CVSS 3.1
7.4 HighCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:H
CVSS 3.0
5.9 MediumCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
OSVCLSA-2024-1735122554 No score

ntp: Fix of CVE-2020-13817

  • CVE-2020-13817: randomize transmit timestamp in client requests
Record
CLSA-2024-1735122554
Updated
2026-11-02
OSVCLSA-2024-1735128099 No score

ntp: Fix of CVE-2020-13817

  • CVE-2020-13817: randomize transmit timestamp in client requests
Record
CLSA-2024-1735128099
Updated
2026-11-02
OSVopenSUSE-SU-2020:0934-1 No score

Security update for ntp

This update for ntp fixes the following issues:

ntp was updated to 4.2.8p15

  • CVE-2020-11868: Fixed an issue which a server mode packet with spoofed source address frequently send to the client ntpd could have caused denial of service (bsc#1169740).
  • CVE-2018-8956: Fixed an issue which could have allowed remote attackers to prevent a broadcast client from synchronizing its clock with a broadcast NTP server via spoofed mode 3 and mode 5 packets (bsc#1171355).
  • CVE-2020-13817: Fixed an issue which an off-path attacker with the ability to query time from victim's ntpd instance could have modified the victim's clock by a limited amount (bsc#1172651).
  • CVE-2020-15025: Fixed an issue which remote attacker could have caused denial of service by consuming the memory when a CMAC key was used andassociated with a CMAC algorithm in the ntp.keys (bsc#1173334).
  • Removed an OpenSSL version warning (bsc#992038 and bsc#1125401).

This update was imported from the SUSE:SLE-15:Update update project.

Record
openSUSE-SU-2020:0934-1
Updated
2026-11-02
OSVopenSUSE-SU-2020:1007-1 No score

Security update for ntp

This update for ntp fixes the following issues:

ntp was updated to 4.2.8p15

  • CVE-2020-11868: Fixed an issue which a server mode packet with spoofed source address frequently send to the client ntpd could have caused denial of service (bsc#1169740).
  • CVE-2018-8956: Fixed an issue which could have allowed remote attackers to prevent a broadcast client from synchronizing its clock with a broadcast NTP server via spoofed mode 3 and mode 5 packets (bsc#1171355).
  • CVE-2020-13817: Fixed an issue which an off-path attacker with the ability to query time from victim's ntpd instance could have modified the victim's clock by a limited amount (bsc#1172651).
  • CVE-2020-15025: Fixed an issue which remote attacker could have caused denial of service by consuming the memory when a CMAC key was used andassociated with a CMAC algorithm in the ntp.keys (bsc#1173334).
  • Removed an OpenSSL version warning (bsc#992038 and bsc#1125401).

This update was imported from the SUSE:SLE-15:Update update project.

Record
openSUSE-SU-2020:1007-1
Updated
2026-11-02
OSVopenSUSE-SU-2024:11102-1 No score

ntp-4.2.8p15-7.2 on GA media

These are all security issues fixed in the ntp-4.2.8p15-7.2 package on the GA media of openSUSE Tumbleweed.

Record
openSUSE-SU-2024:11102-1
Updated
2026-11-02
OSVSUSE-SU-2020:14415-1 No score

Security update for ntp

This update for ntp fixes the following issues:

ntp was updated to 4.2.8p15

  • CVE-2020-11868: Fixed an issue which a server mode packet with spoofed source address frequently send to the client ntpd could have caused denial of service (bsc#1169740).
  • CVE-2018-8956: Fixed an issue which could have allowed remote attackers to prevent a broadcast client from synchronizing its clock with a broadcast NTP server via spoofed mode 3 and mode 5 packets (bsc#1171355).
  • CVE-2020-13817: Fixed an issue which an off-path attacker with the ability to query time from victim's ntpd instance could have modified the victim's clock by a limited amount (bsc#1172651).
  • CVE-2020-15025: Fixed an issue which remote attacker could have caused denial of service by consuming the memory when a CMAC key was used andassociated with a CMAC algorithm in the ntp.keys (bsc#1173334).
Record
SUSE-SU-2020:14415-1
Updated
2026-11-02
OSVSUSE-SU-2020:1805-1 No score

Security update for ntp

This update for ntp fixes the following issues:

ntp was updated to 4.2.8p15

  • CVE-2020-11868: Fixed an issue which a server mode packet with spoofed source address frequently send to the client ntpd could have caused denial of service (bsc#1169740).
  • CVE-2018-8956: Fixed an issue which could have allowed remote attackers to prevent a broadcast client from synchronizing its clock with a broadcast NTP server via spoofed mode 3 and mode 5 packets (bsc#1171355).
  • CVE-2020-13817: Fixed an issue which an off-path attacker with the ability to query time from victim's ntpd instance could have modified the victim's clock by a limited amount (bsc#1172651).
  • CVE-2020-15025: Fixed an issue which remote attacker could have caused denial of service by consuming the memory when a CMAC key was used andassociated with a CMAC algorithm in the ntp.keys (bsc#1173334).
Record
SUSE-SU-2020:1805-1
Updated
2026-11-02
OSVSUSE-SU-2020:1823-1 No score

Security update for ntp

This update for ntp fixes the following issues:

ntp was updated to 4.2.8p15

  • CVE-2020-11868: Fixed an issue which a server mode packet with spoofed source address frequently send to the client ntpd could have caused denial of service (bsc#1169740).
  • CVE-2018-8956: Fixed an issue which could have allowed remote attackers to prevent a broadcast client from synchronizing its clock with a broadcast NTP server via spoofed mode 3 and mode 5 packets (bsc#1171355).
  • CVE-2020-13817: Fixed an issue which an off-path attacker with the ability to query time from victim's ntpd instance could have modified the victim's clock by a limited amount (bsc#1172651).
  • CVE-2020-15025: Fixed an issue which remote attacker could have caused denial of service by consuming the memory when a CMAC key was used andassociated with a CMAC algorithm in the ntp.keys (bsc#1173334).
  • Removed an OpenSSL version warning (bsc#992038 and bsc#1125401).
Record
SUSE-SU-2020:1823-1
Updated
2026-11-02

Affected products

Show 13 moreShow less

Affected packages

Affected packages
PackageAffectedFixed
ntp
TuxCare:CentOS:6
 before 4.2.6p5-16.el6.tuxcare.els1
4.2.6p5-16.el6.tuxcare.els1
ntp-doc
TuxCare:CentOS:6
 before 4.2.6p5-16.el6.tuxcare.els1
4.2.6p5-16.el6.tuxcare.els1
ntp-perl
TuxCare:CentOS:6
 before 4.2.6p5-16.el6.tuxcare.els1
4.2.6p5-16.el6.tuxcare.els1
ntpdate
TuxCare:CentOS:6
 before 4.2.6p5-16.el6.tuxcare.els1
4.2.6p5-16.el6.tuxcare.els1
ntp
TuxCare:OracleLinux:6
 before 4.2.6p5-16.el6.tuxcare.els1
4.2.6p5-16.el6.tuxcare.els1
ntp-doc
TuxCare:OracleLinux:6
 before 4.2.6p5-16.el6.tuxcare.els1
4.2.6p5-16.el6.tuxcare.els1
ntp-perl
TuxCare:OracleLinux:6
 before 4.2.6p5-16.el6.tuxcare.els1
4.2.6p5-16.el6.tuxcare.els1
ntpdate
TuxCare:OracleLinux:6
 before 4.2.6p5-16.el6.tuxcare.els1
4.2.6p5-16.el6.tuxcare.els1
ntp
Debian:11
 before 1:4.2.8p14+dfsg-1
1:4.2.8p14+dfsg-1
ntp
Red Hat:enterprise_linux:7::client
 before 0:4.2.6p5-29.el7_8.2
0:4.2.6p5-29.el7_8.2
Show 51 moreShow less
Affected packages
PackageAffectedFixed
ntp-debuginfo
Red Hat:enterprise_linux:7::client
 before 0:4.2.6p5-29.el7_8.2
0:4.2.6p5-29.el7_8.2
ntpdate
Red Hat:enterprise_linux:7::client
 before 0:4.2.6p5-29.el7_8.2
0:4.2.6p5-29.el7_8.2
ntp-doc
Red Hat:enterprise_linux:7::client
 before 0:4.2.6p5-29.el7_8.2
0:4.2.6p5-29.el7_8.2
ntp-perl
Red Hat:enterprise_linux:7::client
 before 0:4.2.6p5-29.el7_8.2
0:4.2.6p5-29.el7_8.2
sntp
Red Hat:enterprise_linux:7::client
 before 0:4.2.6p5-29.el7_8.2
0:4.2.6p5-29.el7_8.2
ntp
Red Hat:enterprise_linux:7::computenode
 before 0:4.2.6p5-29.el7_8.2
0:4.2.6p5-29.el7_8.2
ntp-debuginfo
Red Hat:enterprise_linux:7::computenode
 before 0:4.2.6p5-29.el7_8.2
0:4.2.6p5-29.el7_8.2
ntpdate
Red Hat:enterprise_linux:7::computenode
 before 0:4.2.6p5-29.el7_8.2
0:4.2.6p5-29.el7_8.2
ntp-doc
Red Hat:enterprise_linux:7::computenode
 before 0:4.2.6p5-29.el7_8.2
0:4.2.6p5-29.el7_8.2
ntp-perl
Red Hat:enterprise_linux:7::computenode
 before 0:4.2.6p5-29.el7_8.2
0:4.2.6p5-29.el7_8.2
sntp
Red Hat:enterprise_linux:7::computenode
 before 0:4.2.6p5-29.el7_8.2
0:4.2.6p5-29.el7_8.2
ntp
Red Hat:enterprise_linux:7::server
 before 0:4.2.6p5-29.el7_8.2
0:4.2.6p5-29.el7_8.2
ntp-debuginfo
Red Hat:enterprise_linux:7::server
 before 0:4.2.6p5-29.el7_8.2
0:4.2.6p5-29.el7_8.2
ntpdate
Red Hat:enterprise_linux:7::server
 before 0:4.2.6p5-29.el7_8.2
0:4.2.6p5-29.el7_8.2
ntp-doc
Red Hat:enterprise_linux:7::server
 before 0:4.2.6p5-29.el7_8.2
0:4.2.6p5-29.el7_8.2
ntp-perl
Red Hat:enterprise_linux:7::server
 before 0:4.2.6p5-29.el7_8.2
0:4.2.6p5-29.el7_8.2
sntp
Red Hat:enterprise_linux:7::server
 before 0:4.2.6p5-29.el7_8.2
0:4.2.6p5-29.el7_8.2
ntp
Red Hat:enterprise_linux:7::workstation
 before 0:4.2.6p5-29.el7_8.2
0:4.2.6p5-29.el7_8.2
ntp-debuginfo
Red Hat:enterprise_linux:7::workstation
 before 0:4.2.6p5-29.el7_8.2
0:4.2.6p5-29.el7_8.2
ntpdate
Red Hat:enterprise_linux:7::workstation
 before 0:4.2.6p5-29.el7_8.2
0:4.2.6p5-29.el7_8.2
ntp-doc
Red Hat:enterprise_linux:7::workstation
 before 0:4.2.6p5-29.el7_8.2
0:4.2.6p5-29.el7_8.2
ntp-perl
Red Hat:enterprise_linux:7::workstation
 before 0:4.2.6p5-29.el7_8.2
0:4.2.6p5-29.el7_8.2
sntp
Red Hat:enterprise_linux:7::workstation
 before 0:4.2.6p5-29.el7_8.2
0:4.2.6p5-29.el7_8.2
ntp
SUSE:Linux Enterprise Server 11 SP4-LTSS
 before 4.2.8p15-64.16.1
4.2.8p15-64.16.1
ntp
SUSE:HPE Helion OpenStack 8
 before 4.2.8p15-88.1
4.2.8p15-88.1
ntp
SUSE:OpenStack Cloud 7
 before 4.2.8p15-88.1
4.2.8p15-88.1
ntp
SUSE:OpenStack Cloud 8
 before 4.2.8p15-88.1
4.2.8p15-88.1
ntp
SUSE:OpenStack Cloud Crowbar 8
 before 4.2.8p15-88.1
4.2.8p15-88.1
ntp
SUSE:Linux Enterprise Server for SAP Applications 12 SP2
 before 4.2.8p15-88.1
4.2.8p15-88.1
ntp
SUSE:Linux Enterprise Server for SAP Applications 12 SP3
 before 4.2.8p15-88.1
4.2.8p15-88.1
ntp
SUSE:Linux Enterprise Server 12 SP2-LTSS
 before 4.2.8p15-88.1
4.2.8p15-88.1
ntp
SUSE:Linux Enterprise Server 12 SP2-BCL
 before 4.2.8p15-88.1
4.2.8p15-88.1
ntp
SUSE:Linux Enterprise Server 12 SP3-LTSS
 before 4.2.8p15-88.1
4.2.8p15-88.1
ntp
SUSE:Linux Enterprise Server 12 SP3-BCL
 before 4.2.8p15-88.1
4.2.8p15-88.1
ntp
SUSE:Linux Enterprise Server 12 SP4
 before 4.2.8p15-88.1
4.2.8p15-88.1
ntp
SUSE:Linux Enterprise Server for SAP Applications 12 SP4
 before 4.2.8p15-88.1
4.2.8p15-88.1
ntp
SUSE:Linux Enterprise Server 12 SP5
 before 4.2.8p15-88.1
4.2.8p15-88.1
ntp
SUSE:Linux Enterprise Server for SAP Applications 12 SP5
 before 4.2.8p15-88.1
4.2.8p15-88.1
ntp
SUSE:Enterprise Storage 5
 before 4.2.8p15-88.1
4.2.8p15-88.1
ntp
SUSE:Linux Enterprise Module for Legacy 15 SP1
 before 4.2.8p15-4.10.1
4.2.8p15-4.10.1
ntp
SUSE:Linux Enterprise Module for Legacy 15 SP2
 before 4.2.8p15-4.10.1
4.2.8p15-4.10.1
ntp
SUSE:Linux Enterprise Server 15-LTSS
 before 4.2.8p15-4.10.1
4.2.8p15-4.10.1
ntp
SUSE:Linux Enterprise Server for SAP Applications 15
 before 4.2.8p15-4.10.1
4.2.8p15-4.10.1
ntp
Ubuntu:Pro:14.04:LTS
 All versions, plus listed versions
1:4.2.6.p5+dfsg-3ubuntu21:4.2.6.p5+dfsg-3ubuntu2.14.04.11:4.2.6.p5+dfsg-3ubuntu2.14.04.21:4.2.6.p5+dfsg-3ubuntu2.14.04.31:4.2.6.p5+dfsg-3ubuntu2.14.04.5
Show 8 moreShow less
1:4.2.6.p5+dfsg-3ubuntu2.14.04.61:4.2.6.p5+dfsg-3ubuntu2.14.04.71:4.2.6.p5+dfsg-3ubuntu2.14.04.81:4.2.6.p5+dfsg-3ubuntu2.14.04.101:4.2.6.p5+dfsg-3ubuntu2.14.04.111:4.2.6.p5+dfsg-3ubuntu2.14.04.121:4.2.6.p5+dfsg-3ubuntu2.14.04.131:4.2.6.p5+dfsg-3ubuntu2.14.04.13+esm1
 None known
ntp
Ubuntu:16.04:LTS
 All versions, plus listed versions
1:4.2.6.p5+dfsg-3ubuntu81:4.2.6.p5+dfsg-3ubuntu8.11:4.2.6.p5+dfsg-3ubuntu91:4.2.8p4+dfsg-3ubuntu11:4.2.8p4+dfsg-3ubuntu2
Show 13 moreShow less
1:4.2.8p4+dfsg-3ubuntu31:4.2.8p4+dfsg-3ubuntu41:4.2.8p4+dfsg-3ubuntu51:4.2.8p4+dfsg-3ubuntu5.11:4.2.8p4+dfsg-3ubuntu5.21:4.2.8p4+dfsg-3ubuntu5.31:4.2.8p4+dfsg-3ubuntu5.41:4.2.8p4+dfsg-3ubuntu5.51:4.2.8p4+dfsg-3ubuntu5.61:4.2.8p4+dfsg-3ubuntu5.71:4.2.8p4+dfsg-3ubuntu5.81:4.2.8p4+dfsg-3ubuntu5.91:4.2.8p4+dfsg-3ubuntu5.10
 None known
ntp
Ubuntu:Pro:18.04:LTS
 All versions, plus listed versions
1:4.2.8p10+dfsg-5ubuntu31:4.2.8p10+dfsg-5ubuntu41:4.2.8p10+dfsg-5ubuntu51:4.2.8p10+dfsg-5ubuntu61:4.2.8p10+dfsg-5ubuntu7
Show 7 moreShow less
1:4.2.8p10+dfsg-5ubuntu7.11:4.2.8p10+dfsg-5ubuntu7.1+esm11:4.2.8p10+dfsg-5ubuntu7.1+esm21:4.2.8p10+dfsg-5ubuntu7.21:4.2.8p10+dfsg-5ubuntu7.2+esm11:4.2.8p10+dfsg-5ubuntu7.31:4.2.8p10+dfsg-5ubuntu7.3+esm1
 None known
ntp
Ubuntu:Pro:20.04:LTS
 All versions, plus listed versions
1:4.2.8p12+dfsg-3ubuntu21:4.2.8p12+dfsg-3ubuntu31:4.2.8p12+dfsg-3ubuntu41:4.2.8p12+dfsg-3ubuntu4.20.04.11:4.2.8p12+dfsg-3ubuntu4.20.04.1+esm1
 None known
ntp
Ubuntu:22.04:LTS
 All versions, plus listed versions
1:4.2.8p12+dfsg-3ubuntu61:4.2.8p15+dfsg-1ubuntu11:4.2.8p15+dfsg-1ubuntu2
 None known
ntp
openSUSE:Leap 15.1
 before 4.2.8p15-lp151.2.3.1
4.2.8p15-lp151.2.3.1
ntp
openSUSE:Leap 15.2
 before 4.2.8p15-lp152.3.3.1
4.2.8p15-lp152.3.3.1
ntp
openSUSE:Tumbleweed
 before 4.2.8p15-7.2
4.2.8p15-7.2

History

History
WhenChangedSources
2026-11-02createdCVE List, EUVD, GitHub Advisories, NVD, OSV

References

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