Description
The rate limiting feature in NTP 4.x before 4.2.8p4 and 4.3.x before 4.3.77 allows remote attackers to have unspecified impact via a large number of crafted requests.
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-3 | — |
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 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP1 | ntp | 4.2.8p7-11.1 | SUSE-SU-2016:1291-1 |
| SLES 12 | ntp | 4.2.8p6-46.5.2 | SUSE-SU-2016:1568-1, 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 | 4.2.8p4-5.1 | SUSE-SU-2016:1278-1, SUSE-SU-2015:2058-1 |
| SLES 11 SP3 | ntp | 4.2.8p6-41.1 | SUSE-SU-2016:1471-1, SUSE-SU-2016:1311-1 |
| SLES 11 SP2 | ntp | 4.2.8p6-41.1 | SUSE-SU-2016:1471-1, 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 | 4.2.8p7-11.1 | SUSE-SU-2016:1291-1 |
| SLES for SAP 12 | ntp | 4.2.8p6-46.5.2 | SUSE-SU-2016:1568-1, 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 | 4.2.8p4-5.1 | SUSE-SU-2016:1278-1, SUSE-SU-2015:2058-1 |
| SUSE OpenStack Cloud 5 | ntp | 4.2.8p6-41.1 | SUSE-SU-2016:1471-1, SUSE-SU-2016:1311-1 |
| SUSE Manager Proxy 2.1 | ntp | 4.2.8p6-41.1 | SUSE-SU-2016:1471-1, SUSE-SU-2016:1311-1 |
| SUSE Manager 2.1 | ntp | 4.2.8p6-41.1 | SUSE-SU-2016:1471-1, 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 |
Advisories 14
- 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-2015:2058-1 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-2016:1471-1 Security update for ntp SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2016:1568-1 Security update for ntp SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2016:1291-1 Security update for ntp SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2016:1278-1 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-2016:1912 vendor-advisory
- VU#718152 third-party-advisory
- USN-2783-1 vendor-advisory
- SUSE-SU-2016:1247 vendor-advisory
- 77284 vdb-entry
- https://support.citrix.com/article/CTX220112
- 1033951 vdb-entry
- http://support.ntp.org/bin/view/Main/SecurityNotice#October_2015_NTP_4_2_8p4_Securit
- SUSE-SU-2016:1311 vendor-advisory
- https://www.cs.bu.edu/~goldbe/NTPattack.html
- SUSE-SU-2016:2094 vendor-advisory
- https://eprint.iacr.org/2015/1020.pdf
- https://h20566.www2.hpe.com/portal/site/hpsc/public/kb/docDisplay?docId=emr_na-c05270839
- https://bugzilla.redhat.com/show_bug.cgi?id=1274184
- http://support.ntp.org/bin/view/Main/NtpBug2901
- openSUSE-SU-2016:1423 vendor-advisory
- GLSA-201607-15 vendor-advisory
- https://security.netapp.com/advisory/ntap-20171004-0001/
- http://packetstormsecurity.com/files/134137/Slackware-Security-Advisory-ntp-Updates.html
- openSUSE-SU-2016:1329 vendor-advisory
- 20151021 Multiple Vulnerabilities in ntpd Affecting Cisco Products - October 2015 vendor-advisory
- SUSE-SU-2016:1471 vendor-advisory
- https://bto.bluecoat.com/security-advisory/sa103
- SUSE-SU-2016:1291 vendor-advisory
- SUSE-SU-2016:1568 vendor-advisory
- openSUSE-SU-2015:2016 vendor-advisory
- SUSE-SU-2016:1278 vendor-advisory
- 20151029 [slackware-security] ntp (SSA:2015-302-03) mailing-list
- 20151029 [slackware-security] ntp (SSA:2015-302-03) mailing-list
- 20151022 Cisco Security Advisory: Multiple Vulnerabilities in ntpd Affecting Cisco Products - October 2015 mailing-list
- 20151022 Cisco Security Advisory: Multiple Vulnerabilities in ntpd Affecting Cisco Products - October 2015 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
- https://www.arista.com/en/support/advisories-notices/security-advisories/1212-security-advisory-0016