CVE-2016-7426

Name: CVE-2016-7426
Creator: NVD / NIST
Published: 2017-01-13T16:59:00.323+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 12.37%

Last modified Jun 17, 2026

CVE-2016-7426 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. 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.. EPSS estimates a 12.37% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

7.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS Probability

12.37%

95.7th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-400

Affected Software

Vendor	Product	Versions	Update
Ntp	Ntp	>= 4.2.6, < 4.2.8	—
Ntp	Ntp	>= 4.3.0, < 4.3.94	—
Ntp	Ntp	4.2.5	P203
Ntp	Ntp	4.2.8	—
Canonical	Ubuntu Linux	12.04	—
Redhat	Enterprise Linux Desktop	6.0	—
Redhat	Enterprise Linux Desktop	7.0	—
Redhat	Enterprise Linux Server	6.0	—
Redhat	Enterprise Linux Server	7.0	—
Redhat	Enterprise Linux Server Aus	7.3	—
Redhat	Enterprise Linux Server Aus	7.4	—
Redhat	Enterprise Linux Server Aus	7.6	—
Redhat	Enterprise Linux Server Aus	7.7	—
Redhat	Enterprise Linux Server Eus	7.3	—
Redhat	Enterprise Linux Server Eus	7.4	—
Redhat	Enterprise Linux Server Eus	7.5	—
Redhat	Enterprise Linux Server Eus	7.6	—
Redhat	Enterprise Linux Server Eus	7.7	—
Redhat	Enterprise Linux Server Tus	7.3	—
Redhat	Enterprise Linux Server Tus	7.6	—
Redhat	Enterprise Linux Server Tus	7.7	—
Redhat	Enterprise Linux Workstation	6.0	—
Redhat	Enterprise Linux Workstation	7.0	—
Hpe	Hpux-Ntp	>= b.11.31, < c.4.2.8.2.0	—

References

http://nwtime.org/ntp428p9_release/Third Party Advisory
http://rhn.redhat.com/errata/RHSA-2017-0252.htmlThird Party Advisory
http://support.ntp.org/bin/view/Main/NtpBug3071Issue Tracking, Mitigation, Vendor Advisory
http://support.ntp.org/bin/view/Main/SecurityNotice#Recent_VulnerabilitiesRelease Notes, Vendor Advisory
http://www.securityfocus.com/bid/94451Third Party Advisory, VDB Entry
http://www.securitytracker.com/id/1037354Third Party Advisory, VDB Entry
https://bto.bluecoat.com/security-advisory/sa139Third Party Advisory
https://h20566.www2.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbux03706en_usThird Party Advisory
https://security.FreeBSD.org/advisories/FreeBSD-SA-16:39.ntp.ascThird Party Advisory
https://usn.ubuntu.com/3707-2/Third Party Advisory
https://www.kb.cert.org/vuls/id/633847Third Party Advisory, US Government Resource
http://nwtime.org/ntp428p9_release/Third Party Advisory
http://rhn.redhat.com/errata/RHSA-2017-0252.htmlThird Party Advisory
http://support.ntp.org/bin/view/Main/NtpBug3071Issue Tracking, Mitigation, Vendor Advisory
http://support.ntp.org/bin/view/Main/SecurityNotice#Recent_VulnerabilitiesRelease Notes, Vendor Advisory
http://www.securityfocus.com/bid/94451Third Party Advisory, VDB Entry
http://www.securitytracker.com/id/1037354Third Party Advisory, VDB Entry
https://bto.bluecoat.com/security-advisory/sa139Third Party Advisory
https://h20566.www2.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbux03706en_usThird Party Advisory
https://security.FreeBSD.org/advisories/FreeBSD-SA-16:39.ntp.ascThird Party Advisory
https://usn.ubuntu.com/3707-2/Third Party Advisory
https://www.kb.cert.org/vuls/id/633847Third Party Advisory, US Government Resource

Timeline

Published: Jan 13, 2017
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2016-7426?

How severe is CVE-2016-7426?

CVE-2016-7426 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 12.37% probability of exploitation in the next 30 days.

How do I fix CVE-2016-7426?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2016-7426?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST