Description
ntpd in ntp before 4.2.8p14 and 4.3.x before 4.3.100 allows an off-path attacker to block unauthenticated synchronization via a server mode packet with a spoofed source IP address, because transmissions are rescheduled even when a packet lacks a valid origin timestamp.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 11 | ntp | 1:4.2.8p14+dfsg-1 | — |
| Debian 8 | ntp | 1:4.2.6.p5+dfsg-7+deb8u3 | DLA-2201-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 22.04 LTS | ntp | No fix yet | — |
| Ubuntu 16.04 LTS | ntp | No fix yet | — |
Show 3 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 20.04 LTS | ntp | No fix yet | — |
| Ubuntu Pro 18.04 LTS | ntp | No fix yet | — |
| Ubuntu Pro 14.04 LTS | ntp | No fix yet | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 7 | ntp +4 | 4.2.6p5-29.el7_8.2 | RHSA-2020:2663 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP2 | ntp | 4.2.8p15-4.10.1 | SUSE-SU-2020:1823-1 |
| SLES 15 SP1 | ntp | 4.2.8p15-4.10.1 | SUSE-SU-2020:1823-1 |
| SLES 15 | ntp | 4.2.8p15-4.10.1 | SUSE-SU-2020:1823-1 |
| SLES 12 SP5 | ntp | 4.2.8p15-88.1 | SUSE-SU-2020:1805-1 |
| SLES 12 SP4 | ntp | 4.2.8p15-88.1 | SUSE-SU-2020:1805-1 |
Show 13 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP3 | ntp | 4.2.8p15-88.1 | SUSE-SU-2020:1805-1 |
| SLES 12 SP2 | ntp | 4.2.8p15-88.1 | SUSE-SU-2020:1805-1 |
| SLES 11 SP4 | ntp | 4.2.8p15-64.16.1 | SUSE-SU-2020:14415-1 |
| SLES for SAP 15 | ntp | 4.2.8p15-4.10.1 | SUSE-SU-2020:1823-1 |
| SLES for SAP 12 SP5 | ntp | 4.2.8p15-88.1 | SUSE-SU-2020:1805-1 |
| SLES for SAP 12 SP4 | ntp | 4.2.8p15-88.1 | SUSE-SU-2020:1805-1 |
| SLES for SAP 12 SP3 | ntp | 4.2.8p15-88.1 | SUSE-SU-2020:1805-1 |
| SLES for SAP 12 SP2 | ntp | 4.2.8p15-88.1 | SUSE-SU-2020:1805-1 |
| SUSE OpenStack Cloud Crowbar 8 | ntp | 4.2.8p15-88.1 | SUSE-SU-2020:1805-1 |
| SUSE OpenStack Cloud 8 | ntp | 4.2.8p15-88.1 | SUSE-SU-2020:1805-1 |
| SUSE OpenStack Cloud 7 | ntp | 4.2.8p15-88.1 | SUSE-SU-2020:1805-1 |
| SUSE HPE Helion OpenStack 8 | ntp | 4.2.8p15-88.1 | SUSE-SU-2020:1805-1 |
| SUSE Enterprise Storage 5 | ntp | 4.2.8p15-88.1 | SUSE-SU-2020:1805-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | ntp | 4.2.8p15-7.2 | openSUSE-SU-2024:11102-1 |
| openSUSE Leap 15.2 | ntp | 4.2.8p15-lp152.3.3.1 | openSUSE-SU-2020:1007-1 |
| openSUSE Leap 15.1 | ntp | 4.2.8p15-lp151.2.3.1 | openSUSE-SU-2020:0934-1 |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2 | ntp +4 | 4.2.6p5-29.amzn2.0.2 | ALAS2-2020-1455 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 7 | ntp +4 | 4.2.6p5-29.0.1.el7_8.2 | ELSA-2020-2663 |
Advisories 14
- RHSA-2020:2663 Red Hat Security Advisory: ntp security update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- WID-SEC-2026-1181 ntp: Schwachstelle ermöglicht Denial of Service BSI CERT-Bund (WID) · Apr 20, 2026
- DLA-2201-1 ntp - security update Debian Security (DSA / DLA) · Mar 9, 2026
- openSUSE-SU-2020:0934-1 Security update for ntp SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2024:11102-1 ntp-4.2.8p15-7.2 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2020:1805-1 Security update for ntp SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2020:1823-1 Security update for ntp SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2020:1007-1 Security update for ntp SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2020:14415-1 Security update for ntp SUSE / openSUSE Security Updates · Feb 4, 2026
- ICSA-23-234-01 Hitachi Energy AFF66x CISA ICS & IT advisories · Aug 22, 2023
- WID-SEC-2023-1737 Juniper Patchday Juli 2023 BSI CERT-Bund (WID) · Jul 12, 2023
- VDE-2022-032 AUMA: Multiple Vulnerabilities in Automation Runtime NTP Service CERT@VDE · Aug 9, 2022
- ALAS2-2020-1455 Moderate: ntp security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · Jul 17, 2020
- ELSA-2020-2663 Moderate: ntp security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Jun 24, 2020
References
- [debian-lts-announce] 20200505 [SECURITY] [DLA 2201-1] ntp security update mailing-list
- openSUSE-SU-2020:0934 vendor-advisory
- openSUSE-SU-2020:1007 vendor-advisory
- GLSA-202007-12 vendor-advisory
- https://www.oracle.com//security-alerts/cpujul2021.html
- http://support.ntp.org/bin/view/Main/NtpBug3592
- https://bugzilla.redhat.com/show_bug.cgi?id=1716665
- https://security.netapp.com/advisory/ntap-20200424-0002/