HOMEVULNERABILITIESCVE-2016-7426
HIGH

CVE-2016-7426

CWE-400Published: January 13, 2017· Updated: Jun 17, 2026

7.5
CVSS v3.1

Official 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.

NVD Source

Technical Analysis

CVE-2016-7426 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in availability disruption (denial of service), with a CVSS base score of 7.5.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.None
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityNone
IntegrityNone
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected Vendors & Products

Canonical1 product(s)
ubuntu linux
hpe1 product(s)
hpux-ntp
ntp1 product(s)
ntp
Red Hat6 product(s)
enterprise linux desktopenterprise linux serverenterprise linux server ausenterprise linux server eusenterprise linux server tusenterprise linux workstation
Source: NVD CPE · 23 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

ADVISORYhttp://nwtime.org/ntp428p9_release/
ADVISORYhttp://rhn.redhat.com/errata/RHSA-2017-0252.html
ADVISORYhttp://support.ntp.org/bin/view/Main/NtpBug3071
ADVISORYhttp://support.ntp.org/bin/view/Main/SecurityNotice#Recent_Vulnerabilities
ADVISORYhttp://www.securityfocus.com/bid/94451
ADVISORYhttp://www.securitytracker.com/id/1037354
ADVISORYhttps://bto.bluecoat.com/security-advisory/sa139
ADVISORYhttps://h20566.www2.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbux03706en_us
ADVISORYhttps://security.FreeBSD.org/advisories/FreeBSD-SA-16:39.ntp.asc
ADVISORYhttps://usn.ubuntu.com/3707-2/
ADVISORYhttps://www.kb.cert.org/vuls/id/633847
ADVISORYhttp://nwtime.org/ntp428p9_release/
ADVISORYhttp://rhn.redhat.com/errata/RHSA-2017-0252.html
ADVISORYhttp://support.ntp.org/bin/view/Main/NtpBug3071
ADVISORYhttp://support.ntp.org/bin/view/Main/SecurityNotice#Recent_Vulnerabilities
ADVISORYhttp://www.securityfocus.com/bid/94451
ADVISORYhttp://www.securitytracker.com/id/1037354
ADVISORYhttps://bto.bluecoat.com/security-advisory/sa139
ADVISORYhttps://h20566.www2.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbux03706en_us
ADVISORYhttps://security.FreeBSD.org/advisories/FreeBSD-SA-16:39.ntp.asc
ADVISORYhttps://usn.ubuntu.com/3707-2/
ADVISORYhttps://www.kb.cert.org/vuls/id/633847

All References (22)

→
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

Quick Facts

CVE IDCVE-2016-7426
CVSS Score7.5 / 10
SeverityHIGH
WeaknessCWE-400
CISA KEVNo
Affected4 vendor(s)
PublishedJan 13, 2017

Related CVEs (CWE-400)

CVE-2015-4412
9.8
CVE-2018-11936
9.8
CVE-2025-43193
9.8
CVE-2017-9119
9.8
CVE-2017-1000378
9.8
CVE-2019-2259
9.8

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2016-7426 in threat intel feeds
  • →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWATCH.COM. CVE data is provided under the NVD usage policy.
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