Description
The panic_gate check in NTP before 4.2.8p5 is only re-enabled after the first change to the system clock that was greater than 128 milliseconds by default, which allows remote attackers to set NTP to an arbitrary time when started with the -g option, or to alter the time by up to 900 seconds otherwise by responding to an unspecified number of requests from trusted sources, and leveraging a resulting denial of service (abort and restart).
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 | 1:4.2.8p4+dfsg-2 | — |
| Debian 8 | ntp | 1:4.2.6.p5+dfsg-7+deb8u1 | DSA-3388-1 |
| Debian 7 | ntp | 1:4.2.6.p5+dfsg-2+deb7u6 | DSA-3388-1 |
| Debian 6.0 | ntp | 1:4.2.6.p2+dfsg-1+deb6u4 | DLA-335-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 14.04 LTS | ntp | 1:4.2.6.p5+dfsg-3ubuntu2.14.04.5 | USN-2783-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 7 | ntp +4 | 4.2.6p5-19.ael7b_1.3 | RHSA-2015:1930 |
| RHEL 6 | ntp +3 | 4.2.6p5-5.el6_7.2 | RHSA-2015:1930 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP1 | ntp | 4.2.8p6-8.2 | SUSE-SU-2016:1177-1 |
| SLES 12 SP1 | yast2-ntp-client | 3.1.22-6.2 | SUSE-SU-2016:1177-1 |
| SLES 12 | ntp | 4.2.8p6-46.5.2 | SUSE-SU-2016:1247-1 |
| SLES 12 | yast2-ntp-client | 3.1.12.4-8.2 | SUSE-SU-2016:1247-1 |
| SLES 11 SP4 | ntp | 4.2.8p6-8.2 | SUSE-SU-2016:1175-1 |
| SLES 11 SP3 | ntp | 4.2.8p6-41.1 | SUSE-SU-2016:1311-1 |
| SLES 11 SP2 | ntp | 4.2.8p6-41.1 | SUSE-SU-2016:1311-1 |
| SLES 11 SP2 | yast2-ntp-client | 2.17.14.1-1.12.1 | SUSE-SU-2016:1311-1 |
Show 6 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 12 SP1 | ntp | 4.2.8p6-8.2 | SUSE-SU-2016:1177-1 |
| SLES for SAP 12 SP1 | yast2-ntp-client | 3.1.22-6.2 | SUSE-SU-2016:1177-1 |
| SLES for SAP 12 | ntp | 4.2.8p6-46.5.2 | SUSE-SU-2016:1247-1 |
| SLES for SAP 12 | yast2-ntp-client | 3.1.12.4-8.2 | SUSE-SU-2016:1247-1 |
| SLES for SAP 11 SP4 | ntp | 4.2.8p6-8.2 | SUSE-SU-2016:1175-1 |
| SUSE OpenStack Cloud 5 | ntp | 4.2.8p6-41.1 | SUSE-SU-2016:1311-1 |
| SUSE Manager Proxy 2.1 | ntp | 4.2.8p6-41.1 | SUSE-SU-2016:1311-1 |
| SUSE Manager 2.1 | ntp | 4.2.8p6-41.1 | SUSE-SU-2016:1311-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | ntp | 4.2.8p9-1.1 | openSUSE-SU-2024:10181-1 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 7 | ntp +4 | 4.2.6p5-19.el7_1.3 | ELSA-2015-1930 |
Advisories 12
- RHSA-2015:1930 Red Hat Security Advisory: ntp security update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- DLA-335-1 ntp - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DSA-3388-1 ntp - security update Debian Security (DSA / DLA) · Mar 9, 2026
- USN-2783-1 ntp vulnerabilities Ubuntu Security Notices (USN) · Feb 10, 2026
- SUSE-SU-2016:1311-1 Security update for ntp SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2016:1177-1 Security update for ntp SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2016:1247-1 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-2016:1175-1 Security update for ntp SUSE / openSUSE Security Updates · Feb 4, 2026
- ICSA-15-356-01 Siemens RUGGEDCOM ROX-based Devices NTP Vulnerabilities CISA ICS & IT advisories · Jun 9, 2025
- VDE-2022-032 AUMA: Multiple Vulnerabilities in Automation Runtime NTP Service CERT@VDE · Aug 9, 2022
- ELSA-2015-1930 Important: ntp security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Oct 26, 2015
References
- RHSA-2015:1930 vendor-advisory
- SUSE-SU:2016:1912 vendor-advisory
- [slackware-security] 20160223 ntp (SSA:2016-054-04) mailing-list
- openSUSE-SU:2016:1423 vendor-advisory
- http://www.oracle.com/technetwork/security-advisory/cpujul2016-2881720.html
- USN-2783-1 vendor-advisory
- SUSE-SU:2016:1177 vendor-advisory
- https://ics-cert.us-cert.gov/advisories/ICSA-15-356-01
- https://www.oracle.com/technetwork/topics/security/linuxbulletinoct2015-2719645.html
- http://support.ntp.org/bin/view/Main/SecurityNotice#January_2016_NTP_4_2_8p5_Securit
- https://bugzilla.redhat.com/show_bug.cgi?id=1271076
- https://www-01.ibm.com/support/docview.wss?uid=swg21980676
- https://support.citrix.com/article/CTX220112
- FEDORA-2015-77bfbc1bcd vendor-advisory
- https://www.ibm.com/support/home/docdisplay?lndocid=migr-5099428
- FEDORA-2015-f5f5ec7b6b vendor-advisory
- DSA-3388 vendor-advisory
- https://www.oracle.com/technetwork/topics/security/bulletinjan2016-2867206.html
- http://aix.software.ibm.com/aix/efixes/security/ntp_advisory5.asc
- https://www.cs.bu.edu/~goldbe/NTPattack.html
- SUSE-SU:2016:2094 vendor-advisory
- FEDORA-2016-34bc10a2c8 vendor-advisory
- 1034670 vdb-entry
- https://www-01.ibm.com/support/docview.wss?uid=isg3T1024073
- 77312 vdb-entry
- SUSE-SU:2016:1311 vendor-advisory
- FreeBSD-SA-16:02 vendor-advisory
- https://www-01.ibm.com/support/docview.wss?uid=swg21979393
- openSUSE-SU:2016:1292 vendor-advisory
- https://www-01.ibm.com/support/docview.wss?uid=nas8N1021264
- SUSE-SU:2016:1247 vendor-advisory
- https://www-01.ibm.com/support/docview.wss?uid=isg3T1023885
- https://bto.bluecoat.com/security-advisory/sa113
- https://www-01.ibm.com/support/docview.wss?uid=swg21983501
- https://www-01.ibm.com/support/docview.wss?uid=ssg1S1005821
- http://support.ntp.org/bin/view/Main/NtpBug2956
- https://www-01.ibm.com/support/docview.wss?uid=swg21983506
- SUSE-SU:2016:1175 vendor-advisory
- https://security.netapp.com/advisory/ntap-20171004-0001/