Vulnerability Monitor

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CVE-2016-7426

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.

Security Impact Summary

This vulnerability carries a HIGH severity rating with a CVSS v3.1 score of 7.5, indicating it can be exploited remotely over the network with relatively low complexity without requiring user interaction and does not require pre-existing privileges . The vulnerability impacts and availability (service disruption) for affected systems. Impacting 9 products from ntp, from canonical, from redhat and 6 others, organizations running these solutions should prioritize assessment and patching.

Historical Context

First disclosed in 2017, this vulnerability was reported during a period defined by widespread IoT adoption challenges, mobile security concerns, and the emergence of advanced persistent threat (APT) techniques. Contemporary mitigation strategies focused on secure development practices and third-party component vetting.

Published

2017-01-13T16:59:00.323

Last Modified

2025-04-20T01:37:25.860

Status

Deferred

Source

[email protected]

Severity

CVSSv3.1: 7.5 (HIGH)

CVSSv2 Vector

AV:N/AC:M/Au:N/C:N/I:N/A:P

Access Vector: NETWORK
Access Complexity: MEDIUM
Authentication: NONE
Confidentiality Impact: NONE
Integrity Impact: NONE
Availability Impact: PARTIAL

Exploitability Score

8.6

Impact Score

2.9

Weaknesses

Type: Primary
CWE-400

Affected Vendors & Products

Type	Vendor	Product	Version/Range	Vulnerable?
Application	ntp	ntp	< 4.2.8	Yes
Application	ntp	ntp	< 4.3.94	Yes
Application	ntp	ntp	4.2.5	Yes
Application	ntp	ntp	4.2.5	Yes
Application	ntp	ntp	4.2.5	Yes
Application	ntp	ntp	4.2.5	Yes
Application	ntp	ntp	4.2.5	Yes
Application	ntp	ntp	4.2.5	Yes
Application	ntp	ntp	4.2.5	Yes
Application	ntp	ntp	4.2.5	Yes
Application	ntp	ntp	4.2.5	Yes
Application	ntp	ntp	4.2.5	Yes
Application	ntp	ntp	4.2.5	Yes
Application	ntp	ntp	4.2.5	Yes
Application	ntp	ntp	4.2.5	Yes
Application	ntp	ntp	4.2.5	Yes
Application	ntp	ntp	4.2.5	Yes
Application	ntp	ntp	4.2.5	Yes
Application	ntp	ntp	4.2.5	Yes
Application	ntp	ntp	4.2.5	Yes
Application	ntp	ntp	4.2.5	Yes
Application	ntp	ntp	4.2.5	Yes
Application	ntp	ntp	4.2.5	Yes
Application	ntp	ntp	4.2.5	Yes
Application	ntp	ntp	4.2.5	Yes
Application	ntp	ntp	4.2.5	Yes
Application	ntp	ntp	4.2.5	Yes
Application	ntp	ntp	4.2.5	Yes
Application	ntp	ntp	4.2.5	Yes
Application	ntp	ntp	4.2.5	Yes
Application	ntp	ntp	4.2.5	Yes
Application	ntp	ntp	4.2.5	Yes
Application	ntp	ntp	4.2.5	Yes
Application	ntp	ntp	4.2.5	Yes
Application	ntp	ntp	4.2.5	Yes
Application	ntp	ntp	4.2.5	Yes
Application	ntp	ntp	4.2.5	Yes
Application	ntp	ntp	4.2.5	Yes
Application	ntp	ntp	4.2.5	Yes
Application	ntp	ntp	4.2.5	Yes
Application	ntp	ntp	4.2.5	Yes
Application	ntp	ntp	4.2.5	Yes
Application	ntp	ntp	4.2.5	Yes
Application	ntp	ntp	4.2.5	Yes
Application	ntp	ntp	4.2.5	Yes
Application	ntp	ntp	4.2.5	Yes
Application	ntp	ntp	4.2.5	Yes
Application	ntp	ntp	4.2.5	Yes
Application	ntp	ntp	4.2.5	Yes
Application	ntp	ntp	4.2.5	Yes
Application	ntp	ntp	4.2.8	Yes
Application	ntp	ntp	4.2.8	Yes
Application	ntp	ntp	4.2.8	Yes
Application	ntp	ntp	4.2.8	Yes
Application	ntp	ntp	4.2.8	Yes
Application	ntp	ntp	4.2.8	Yes
Application	ntp	ntp	4.2.8	Yes
Application	ntp	ntp	4.2.8	Yes
Application	ntp	ntp	4.2.8	Yes
Application	ntp	ntp	4.2.8	Yes
Application	ntp	ntp	4.2.8	Yes
Application	ntp	ntp	4.2.8	Yes
Application	ntp	ntp	4.2.8	Yes
Application	ntp	ntp	4.2.8	Yes
Application	ntp	ntp	4.2.8	Yes
Application	ntp	ntp	4.2.8	Yes
Application	ntp	ntp	4.2.8	Yes
Application	ntp	ntp	4.2.8	Yes
Application	ntp	ntp	4.2.8	Yes
Application	ntp	ntp	4.2.8	Yes
Application	ntp	ntp	4.2.8	Yes
Application	ntp	ntp	4.2.8	Yes
Operating System	canonical	ubuntu_linux	12.04	Yes
Operating System	redhat	enterprise_linux_desktop	6.0	Yes
Operating System	redhat	enterprise_linux_desktop	7.0	Yes
Operating System	redhat	enterprise_linux_server	6.0	Yes
Operating System	redhat	enterprise_linux_server	7.0	Yes
Operating System	redhat	enterprise_linux_server_aus	7.3	Yes
Operating System	redhat	enterprise_linux_server_aus	7.4	Yes
Operating System	redhat	enterprise_linux_server_aus	7.6	Yes
Operating System	redhat	enterprise_linux_server_aus	7.7	Yes
Operating System	redhat	enterprise_linux_server_eus	7.3	Yes
Operating System	redhat	enterprise_linux_server_eus	7.4	Yes
Operating System	redhat	enterprise_linux_server_eus	7.5	Yes
Operating System	redhat	enterprise_linux_server_eus	7.6	Yes
Operating System	redhat	enterprise_linux_server_eus	7.7	Yes
Operating System	redhat	enterprise_linux_server_tus	7.3	Yes
Operating System	redhat	enterprise_linux_server_tus	7.6	Yes
Operating System	redhat	enterprise_linux_server_tus	7.7	Yes
Operating System	redhat	enterprise_linux_workstation	6.0	Yes
Operating System	redhat	enterprise_linux_workstation	7.0	Yes
Application	hpe	hpux-ntp	< c.4.2.8.2.0	Yes

References

http://nwtime.org/ntp428p9_release/ Third Party Advisory ([email protected])
http://rhn.redhat.com/errata/RHSA-2017-0252.html Third Party Advisory ([email protected])
http://support.ntp.org/bin/view/Main/NtpBug3071 Issue Tracking, Mitigation, Vendor Advisory ([email protected])
http://support.ntp.org/bin/view/Main/SecurityNotice#Recent_Vulnerabilities Release Notes, Vendor Advisory ([email protected])
http://www.securityfocus.com/bid/94451 Third Party Advisory, VDB Entry ([email protected])
http://www.securitytracker.com/id/1037354 Third Party Advisory, VDB Entry ([email protected])
https://bto.bluecoat.com/security-advisory/sa139 Third Party Advisory ([email protected])
https://h20566.www2.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbux03706en_us Third Party Advisory ([email protected])
https://security.FreeBSD.org/advisories/FreeBSD-SA-16:39.ntp.asc Third Party Advisory ([email protected])
https://usn.ubuntu.com/3707-2/ Third Party Advisory ([email protected])
https://www.kb.cert.org/vuls/id/633847 Third Party Advisory, US Government Resource ([email protected])
http://nwtime.org/ntp428p9_release/ Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
http://rhn.redhat.com/errata/RHSA-2017-0252.html Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
http://support.ntp.org/bin/view/Main/NtpBug3071 Issue Tracking, Mitigation, Vendor Advisory (af854a3a-2127-422b-91ae-364da2661108)
http://support.ntp.org/bin/view/Main/SecurityNotice#Recent_Vulnerabilities Release Notes, Vendor Advisory (af854a3a-2127-422b-91ae-364da2661108)
http://www.securityfocus.com/bid/94451 Third Party Advisory, VDB Entry (af854a3a-2127-422b-91ae-364da2661108)
http://www.securitytracker.com/id/1037354 Third Party Advisory, VDB Entry (af854a3a-2127-422b-91ae-364da2661108)
https://bto.bluecoat.com/security-advisory/sa139 Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://h20566.www2.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbux03706en_us Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://security.FreeBSD.org/advisories/FreeBSD-SA-16:39.ntp.asc Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://usn.ubuntu.com/3707-2/ Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://www.kb.cert.org/vuls/id/633847 Third Party Advisory, US Government Resource (af854a3a-2127-422b-91ae-364da2661108)

How SecUtils Interprets This CVE

SecUtils normalizes and enriches National Vulnerability Database (NVD) records by standardizing vendor and product identifiers, aggregating vulnerability metadata from both NVD and MITRE sources, and providing structured context for security teams. For ntp's affected products, we extract Common Platform Enumeration (CPE) data, Common Weakness Enumeration (CWE) classifications, CVSS severity metrics, and reference data to enable rapid vulnerability prioritization and asset correlation. This record contains no exploit code, proof-of-concept instructions, or attack methodologies—only defensive intelligence necessary for patch management, risk assessment, and security operations.