What’s Vulnerable › Vulnerabilities
CVE-2016-7426
- Severity: high (CVSS 7.5 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 12.4% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2017-01-13 · updated 2026-06-17
- Weakness: CWE-400
Description
NTP before 4.2.8p9 rate limits responses received from the configured sources when rate limiting for all associations is enabled, which allows remote attackers to cause a denial of service (prevent responses from the sources) by sending responses with a spoofed source address.
Affected products
- Canonical Ubuntu Linux: 12.04
- HPE Hpux-Ntp: from b.11.31 before c.4.2.8.2.0 — fixed in c.4.2.8.2.0
- NTP: from 4.2.6 before 4.2.8; from 4.3.0 before 4.3.94; 4.2.5-p203, 4.2.5-p204, 4.2.5-p205, 4.2.5-p206, 4.2.5-p207, 4.2.5-p208 (+64) — fixed in 4.2.8, 4.3.94
- RedHat Enterprise Linux Desktop: 6.0, 7.0
- RedHat Enterprise Linux Server: 6.0, 7.0
- RedHat Enterprise Linux Server Aus: 7.3, 7.4, 7.6, 7.7
- RedHat Enterprise Linux Server Eus: 7.3, 7.4, 7.5, 7.6, 7.7
- RedHat Enterprise Linux Server Tus: 7.3, 7.6, 7.7
- RedHat Enterprise Linux Workstation: 6.0, 7.0
How to fix
Upgrade to a fixed version: HPE Hpux-Ntp c.4.2.8.2.0; NTP 4.2.8, 4.3.94. Check the vendor advisory for mitigations.
References
- http://nwtime.org/ntp428p9_release/
- http://rhn.redhat.com/errata/RHSA-2017-0252.html
- http://support.ntp.org/bin/view/Main/NtpBug3071
- http://support.ntp.org/bin/view/Main/SecurityNotice#Recent_Vulnerabilities
- http://www.securityfocus.com/bid/94451
- http://www.securitytracker.com/id/1037354
- https://bto.bluecoat.com/security-advisory/sa139
- https://h20566.www2.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbux03706en_us
- https://security.FreeBSD.org/advisories/FreeBSD-SA-16:39.ntp.asc
- https://usn.ubuntu.com/3707-2/
- https://www.kb.cert.org/vuls/id/633847
- http://nwtime.org/ntp428p9_release/
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