MEDIUM
CVE-2016-2516
CWE-20Published: January 30, 2017· Updated: Jun 17, 2026
5.3
CVSS v3.1
Official Description
NTP before 4.2.8p7 and 4.3.x before 4.3.92, when mode7 is enabled, allows remote attackers to cause a denial of service (ntpd abort) by using the same IP address multiple times in an unconfig directive.
Technical Analysis
CVE-2016-2516 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.
Exploitation requires low privileges, which limits the exposure to scenarios where an attacker has already gained initial access.
A successful exploit results in availability disruption (denial of service), with a CVSS base score of 5.3.
CVSS v3.1 Vector Breakdown
Exploitability
Attack VectorNetwork
Attack ComplexityHigh
Privileges Req.Low
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityNone
IntegrityNone
AvailabilityHigh
CVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
Affected Vendors & Products
ntp1 product(s)
ntp
Source: NVD CPE · 93 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
All References (18)
→
http://support.ntp.org/bin/view/Main/NtpBug3011Vendor Advisory
→
http://www.oracle.com/technetwork/topics/security/bulletinapr2016-2952098.htmlThird Party Advisory
→
http://www.securityfocus.com/bid/88180Third Party Advisory · VDB Entry
→
https://www.kb.cert.org/vuls/id/718152Third Party Advisory · US Government Resource
→
http://support.ntp.org/bin/view/Main/NtpBug3011Vendor Advisory
→
http://www.oracle.com/technetwork/topics/security/bulletinapr2016-2952098.htmlThird Party Advisory
→
http://www.securityfocus.com/bid/88180Third Party Advisory · VDB Entry
Quick Facts
CVE IDCVE-2016-2516
CVSS Score5.3 / 10
SeverityMEDIUM
WeaknessCWE-20
CISA KEVNo
Affected1 vendor(s)
PublishedJan 30, 2017
Related CVEs (CWE-20)
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2016-2516 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.