Description
The process_packet function in ntp_proto.c in ntpd in NTP 4.x before 4.2.8p8 allows remote attackers to cause a denial of service (peer-variable modification) by sending spoofed packets from many source IP addresses in a certain scenario, as demonstrated by triggering an incorrect leap indication.
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 | 1:4.2.8p8+dfsg-1 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 16.04 LTS | ntp | 1:4.2.8p4+dfsg-3ubuntu5.3 | USN-3096-1 |
| Ubuntu 14.04 LTS | ntp | 1:4.2.6.p5+dfsg-3ubuntu2.14.04.10 | USN-3096-1 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP1 | ntp | 4.2.8p8-14.1 | SUSE-SU-2016:1563-1 |
| SLES 12 | ntp | 4.2.8p8-46.8.1 | SUSE-SU-2016:1568-1 |
| SLES 11 SP4 | ntp | 4.2.8p8-14.1 | SUSE-SU-2016:1584-1 |
| SLES 11 SP3 | ntp | 4.2.8p8-47.3 | SUSE-SU-2016:1602-1 |
| SLES 11 SP2 | ntp | 4.2.8p8-47.3 | SUSE-SU-2016:1602-1 |
Show 6 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 12 SP1 | ntp | 4.2.8p8-14.1 | SUSE-SU-2016:1563-1 |
| SLES for SAP 12 | ntp | 4.2.8p8-46.8.1 | SUSE-SU-2016:1568-1 |
| SLES for SAP 11 SP4 | ntp | 4.2.8p8-14.1 | SUSE-SU-2016:1584-1 |
| SUSE OpenStack Cloud 5 | ntp | 4.2.8p8-47.3 | SUSE-SU-2016:1602-1 |
| SUSE Manager Proxy 2.1 | ntp | 4.2.8p8-47.3 | SUSE-SU-2016:1602-1 |
| SUSE Manager 2.1 | ntp | 4.2.8p8-47.3 | SUSE-SU-2016:1602-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | ntp | 4.2.8p9-1.1 | openSUSE-SU-2024:10181-1 |
Advisories 11
- USN-3096-1 ntp vulnerabilities Ubuntu Security Notices (USN) · Feb 10, 2026
- SUSE-SU-2016:1602-1 Security update for ntp SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2016:1584-1 Security update for ntp SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2016:1563-1 Security update for ntp SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2024:10181-1 ntp-4.2.8p9-1.1 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2016:1568-1 Security update for ntp SUSE / openSUSE Security Updates · Feb 4, 2026
- ICSA-21-103-11 Siemens TIM 4R-IE Devices CISA ICS & IT advisories · Jun 10, 2025
- SSA-497656 SSA-497656: Multiple NTP Vulnerabilities in TIM 4R-IE Devices Siemens ProductCERT · Jun 10, 2025
- ICSA-21-159-11 Siemens SIMATIC NET CP 443-1 OPC UA CISA ICS & IT advisories · May 6, 2025
- VDE-2022-032 AUMA: Multiple Vulnerabilities in Automation Runtime NTP Service CERT@VDE · Aug 9, 2022
- SSA-211752 SSA-211752: Multiple NTP-Client Related Vulnerabilities in SIMATIC CP 443-1 OPC UA Siemens ProductCERT · Feb 8, 2022
References
- SUSE-SU-2016:1602 vendor-advisory
- USN-3096-1 vendor-advisory
- FEDORA-2016-c3bd6a3496 vendor-advisory
- openSUSE-SU-2016:1583 vendor-advisory
- FreeBSD-SA-16:24 vendor-advisory
- SUSE-SU-2016:1912 vendor-advisory
- FEDORA-2016-89e0874533 vendor-advisory
- https://h20566.www2.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbhf03757en_us
- 1036037 vdb-entry
- SUSE-SU-2016:1584 vendor-advisory
- http://www.oracle.com/technetwork/topics/security/bulletinapr2016-2952098.html
- http://support.ntp.org/bin/view/Main/NtpBug3044
- SUSE-SU-2016:2094 vendor-advisory
- VU#321640 third-party-advisory
- http://support.ntp.org/bin/view/Main/SecurityNotice
- FEDORA-2016-50b0066b7f vendor-advisory
- openSUSE-SU-2016:1636 vendor-advisory
- http://bugs.ntp.org/3044
- SUSE-SU-2016:1563 vendor-advisory
- GLSA-201607-15 vendor-advisory
- http://packetstormsecurity.com/files/137321/Slackware-Security-Advisory-ntp-Updates.html
- 20160603 Multiple Vulnerabilities in Network Time Protocol Daemon Affecting Cisco Products: June 2016 vendor-advisory
- 20170607 [security bulletin] HPESBHF03757 rev.1 - HPE Network Products including Comware 5 and Comware 7 running NTP, Remote Denial of Service (DoS) mailing-list
- http://packetstormsecurity.com/files/137322/FreeBSD-Security-Advisory-FreeBSD-SA-16-24.ntp.html
- SUSE-SU-2016:1568 vendor-advisory
- 20160604 [slackware-security] ntp (SSA:2016-155-01) mailing-list
- 20170607 [security bulletin] HPESBHF03757 rev.1 - HPE Network Products including Comware 5 and Comware 7 running NTP, Remote Denial of Service (DoS) mailing-list
- 20160604 FreeBSD Security Advisory FreeBSD-SA-16:24.ntp mailing-list
- VU#321640 third-party-advisory
- 20160604 [slackware-security] ntp (SSA:2016-155-01) mailing-list
- 20160604 FreeBSD Security Advisory FreeBSD-SA-16:24.ntp mailing-list
- https://cert-portal.siemens.com/productcert/pdf/ssa-497656.pdf
- https://us-cert.cisa.gov/ics/advisories/icsa-21-103-11
- https://cert-portal.siemens.com/productcert/pdf/ssa-211752.pdf
- https://us-cert.cisa.gov/ics/advisories/icsa-21-159-11